U.S.  DEPARTMENT  OF  AGRICULTURE, 

BUFLEAU   O^A44I^At  MI^DU(TrRy.--Bulleti 

ON,    D.   V.   M.,   ChW 


MAR  8    ,3,3$ 


'EXAS  FEVER 


'?_AI 


(OTIII-RWIS1-  KNOWN  AS  TICK   FKYHR.  Sl'LHNKTIC   PKYKR. 
OR  SOITHHRN  lATHI:  FI-VHR). 


METHODS  FOR  ITS  PREVENTION 


JOHN  R.   MOIILER,  V.  M.  D., 
Chief  of  Pathological  Division,  Jinn-ait  of  Animal  Industry. 


WASHINGTON: 

GOVERN'MKN'r     PKI\TIN<;     o  F  K  I  C' K 

1905. 


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U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU   OF  ANIMAL   INDUSTRY.— Bulletin   No.  78. 

D.   E.  SALMON,   D.  V.   M.,   Chief  of  Bureau. 


TEXAS  FEVER 


(OTHERWISE  KNOWN  AS  TICK  FEVER.  SPLENETIC  FEVER, 
OR  SOUTHERN  CATTLE  FEVER), 


METHODS  FOR  ITS  PREVENTION. 


BY 


JOHN  R.  MOHLER,  V.  M.  I)., 

Chief  of  Pathological  Division,  Bureau  of  Animal  Industry. 


WASHINGTON: 

GOVERNMENT     PRIXTIVO    OFFICE. 
1905. 


LETTER  OF  TRANSMITTAL 


U.  8.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ANIMAL  INDUSTRY, 

\Yaxhinyton,  D.  C.,  Auyunt  4.  1905. 

SIR:  I  have  the  honor  to  transmit  herewith  a  manuscript  entitled 
"Texas  fever  (otherwise  known  as  tick  fever,  splenetic  fever,  or 
Southern  cattle  fever),  with  methods  for  its  prevention."  by  John  R. 
Mohler,  V.  M.  D.,  chief  of  the  Pathological  Division  of  this  Bureau. 
This  article  deals  in  a  practical  way  with  :i  disease  which  causes 
great  annual  loss  to  the  stockmen  of  this  country. 

I  recommend  that  this  manuscript  he  published  as  Bulletin  No.  78 
of  the  Bureau  of  Animal  Industry  series. 
Respectfully, 

D.  E.  SALMON. 

Chief  of  Bureau. 
Hon.  JAMES  WILSON, 

Secretary  of  Agriculture. 


COXTKXTS. 


Page. 

Introduction.  5 

Name  and  synonyms.  .  6 

Definition  . .                                                                                            6 

History  and  distribution    .  7 

Cause  of  the  disease  „  9 
Life  history  of  the  cattle  tick  and  the  part  played  by  it  in  producing  Texas 

fever..  10 
How  to  distinguish  harmless  ticks  found  on  cattle  from  Texas  fever  ticks  .  12 
Some  objections  to  the  role  of  ticks  as  carriers  of  Texas  fever,  with  expla- 
nations    15 

Other  injurious  effects  of  cattle  ticks  . .  18 

Loss  occasioned  by  cattle  ticks                                                  19 

Period  of  development  of  disease  after  exposure  to  ticks    .  22 

Symptoms . .  22 

Appearance  after  death    .  25 

Course  and  termination*  .  _  26 

Infective  character  . .  27 

Animals  affected  _  28 

Diseases  mistaken  for  Texas  fever . . 28 

Treatment 29 

Prevention: 

How  to  free  cattle  of  ticks — 

Picking  or  brushing  ticks  off  cattle.  .  30 

Smearing  or  spraying  cattle  with  a  disinfecting  solution  30 

Dipping  in  a  vat .  31 

By  the '' soiling"  method  ..  32 
How  to  free  pastures  of  ticks— 

By  excluding  cattle  for  a  definite  period  . .  33 
By  cultivation    .  33 
By  burning  off  the  grass  . .  33 
How  to  free  cattle  and  pastures  of  ticks  at  the  same  time- 
By  the  "  feed-lot  "  method  .  .  85 

By  pasture  rotation 36 

Immunization  of  susceptible  cattle — 

By  blood  inoculation  39 

By  infesting  with  ticks  42 
Federal  sanitary  regulations 

Other  important  measures  for  reducing  the  infected  area  44 


ILLUSTRATIONS. 


Pa*?. 

PLATE  1,  fig.  1.  Mature  female  cattle  tick  (X  4);  fig.  la.  Mature  female  cattle 
tick  (natural  size):  fig.  Ib.  Head  and  shield  of  same  (X  15):  fig. 
2.  Mature  female  castor-bean  tick  (X  4):  fig.  2a.  Mature  female 
castor-bean  tick  (natural  size):  fig.  2b.  Head  and  shield  of 
same  (X  15);  fig.  :{.  Mature  female  net  tick  (X  4):  fig.  3a.  Ma- 
ture female  net  tick  (natural  size):  fig.  3b.  Head  and  shield  of 
same  (X  15);  fig.  4.  Mature  female  dog,  or  wood,  tick  (X  4): 
fig.  4a.  Mature  female  dog. or  wood,  tick  (natural  size):  fig.  4b. 
Head  and  shield  of  same  (X  15)  Ml 

2,  fig.  1.  Mature  female  Lone  Star  tick  (X4):  fig.  la.  Mature  female 

Lone  Star  tick  (natural  size):  fig.  Ib.  Head  ami  shield  of  same 
(X  15):  fig.  2.  Mature  female  ear  tick  (X  4):  fig.  2a.  Mature 
female  ear  tick  (natural  size):  fig.  2b.  Head  of  same  protruding 
from  beneath  (X  15);  fig.  :{.  Mature  female  clricken  tick  (X  4): 
fig.  :5a.  Mature  female  chicken  tick  (natural  size):  fig.  3b.  Up- 
per portion  of  same,  head  invisible  (X  10):  fig.  4.  Mat  re  female 
European  dog  tick  (X  4):  fig.  4a.  Mature  female  European  dog 
tick  (natural  size);  fig.  4b.  Head  and  shield  of  same  (X  15)  ..  Ifl 

3,  fig.    1.  Larva  of  cattle  tick  (X  25);  fig.  2.  Larva  of  cattle  tick 

(natural  size);  fig.  3.  Mature  female  and  eggs  (natural  size): 
fig.  4.  Hide,  showing  cattle  ticks:  fig.  5.  Blood  cells  containing 
Texas  fever  protozoa:  fig.  <>.  Male  cattle  tick  (X  15);  fig.  7.  Male 
cattle  tick  (natural  size);  fig.  «.  Young  female  cattle  tick  ( X  15): 
fig.  0.  Young  female  cattle  tick  (natural  size):  fig.  10.  Various 
stages  and  colorations  of  cattle  ticks  .  16 


Fn».  1.  Boundary  line  of  the  district  infected  with  Texas  fever 

2.  (leaning  cattle  and  soil  by  "  feed-lot  "  method 

3.  (leaning  cattle  and  soil  by  pasture  rotation   

4 


TEXAS  FEVER 

(Otherwise  known  as  Tick  Fever.  Splenetie  Fever.  «r  Southern  Tattle  Fever). 
WITH  METHODS  FOR  ITS  PREVENTION. 

Hy  JOHN   It.  MOIII.KK.  V.  M.  I).. 
Chief  of  I'dtitiilot/icul  IHrixioii,  Iturrttu  of  Animal  Inthixtry. 

[NTKODUCTION. 

Texas  fever,  a  very  serious  obstacle  to  the  development  and  pros- 
perity of  the  cattle  industry  of  the  South,  has  been  pretty  thoroughly 
understood  since  the  investigations  and  discoveries  made  by  Smith 
and  Kilborne  and  published  in  181)8  as  Bulletin  No.  1  of  the  Bureau 
of  Animal  Industry.  Their  work  showed  conclusively  that  the 
cause  of  the  disease  was  an  intracorpuscular  parasite  (one  living 
within  the  blood  cells),  the  intermediate  stage  of  the  development  of 
which  occurred  in  the  cattle  tick,  thus  making  this  tick  the  indirect 
but  absolutely  essential  factor  in  the  natural  production  of  the  dis- 
ease. Above  the  latitude  where  the  cattle  tick  is  destroyed  by  the 
cold  of  winter  the  disease  can  be  thoroughly  controlled  by  keeping 
Southern  tick-infested  cattle  from  passing  through  the  country  dur- 
ing certain  seasons.  It  is  also  well  known  that  by  completely  sever- 
ing the  relations  of  the  fever  tick  and  native  cattle  the  former  may 
be  exterminated,  thus  making  it  possible  by  intelligent  and  energetic 
measures  to  eradicate  the  disease,  and  thereby  to  remove  a  constant 
menace*  to  the  Southern  cattle  breeder,  feeder,  and  dairyman.  In 
spite  of  these  facts,  however,  comparatively  little  work  has  l>een  done 
along  the  line  of  controlling  this  disease  in  the  infected  districts 
either  by  State  legislation,  by  county  or  parish  regulations,  or  by  the 
combined  action  of  cattle  breeders  over  a  large  extent  of  country. 
This  probably  has  been  due  in  a  great  measure  to  a  lack  of  knowledge 
or  indifference  on  the  part  of  legislators  and  farmers  to  the  advan- 
tage which  may  accrue  from  their  combined  efforts.  It  is  with  the 
object  of  stimulating  (hem  and  suggesting  plans  to  eradicate  the  cat- 
tle tick,  and  thereby  to  enable  stock  owners  of  the  South  to  esi'ajH1 
the  loss  of  millions  of  dollars  annually  sustained  by  them  as  a  result 
of  its  devastations,  that  this  bulletin  is  issued.  Especial  pains  will 
be  taken  to  make  as  clear  as  possible  the  absolutely  proved  facts  re- 


<)  BUREAU  OF  ANIMAL  INDUSTRY. 

garding  the  disease,  so  that  every  cattle  owner  will  IK'  able  to  recog- 
nize the  malady  and  the  tick  which  causes  it,  and  to  carry  out 
successfully  measures  for  eliminating  this  tick  as  well  as  for  immu- 
nizing cattle  brought  into  the  infected  area. 

NAMF,    AND    SYNONYMS. 

Of  the  long  list  of  terms  applied  to  this  disease,  none  seems  to  fill 
completely  all  the  requirements  of  an  ideal  name.  "  Texas  fever," 
although  the  term  most  commonly  in  use  in  this  country,  is  a  very 
misleading  one,  as  it  gives  to  the  uninformed  the  impression  that 
the  disease  is  confined  to  the  State  of  Texas.  Southern  cattle  fever 
is  especially  inapplicable,  as  the  disease  is  usually  more  virulent  in 
Northern  cattle  when  once  infection  becomes  manifest  than  in 
Southern  cattle.  Probably  the  best  name  to  apply  to  the  disease, 
since  it  can  only  be  transmitted  in  nature  by  the  tick  ftooj>hilut<  an- 
nulatw,  is  that  of  tick  fever.  This  designation,  however,  is  com- 
paratively little  used,  and,  as  the  disease  is  generally  recognized  in 
this  country  under  the  name  of  Texas  fever,  this  term  will  be  used 
in  the  present  work.  Other  synonyms  besides  those  already  men 
tioned  are  red  water,  black  water,  distemper,  acclimation  fever,  mur- 
rain, dry  murrain,  yellow  murrain,  bloody  murrain,  Mexican  fever, 
Spanish  fever,  splenic  (or  splenetic)  fever,  protozoan  cattle  fever, 
hemaglobinuria.  tristeza.  paludism  of  cattle,  bovine  periodic  fever, 
bovine  piroplasmosis,  and  bovine  malaria. 

DEFINITION. 

Texas  fever  is  a  specific  infectious  disease  of  the  blood  of  cattle, 
caused  by  the  development  and  activity  of  minute  animal  parasites 
(protozoa)  which  are  conveyed  to  the  affected  animals  by  means  of 
the  cattle  tick  Boophiliw  annulatuft.  After  the  microscopic  pro- 
tozoan is  injected  into  the  blood  of  a  susceptible  animal  it  attacks  the. 
red  blood  cells,  causing  their  disintegration.  The  disease  is  charac- 
terized by  high  fever,  by  destruction  of  red  corpuscles,  and  the  con- 
sequent excretion  of  the  coloring  matter  of  the  blood  by  the  kidneys, 
causing  a  reddish  discoloration  of  the  urine,  by  enlarged  spleen, 
engorged  liver,  thick,  flaky  bile,  more  or  less  jaundice,  emaciation, 
and  death  in  from  10  per  cent  of  the  chronic  to  JK)  per  cent  of  the 
acute  cases.  The  peculiarity  about  this  disease  is  that  the  animals 
responsible  for  the  spread  of  the  malady  are  apparently  healthy,  al- 
though containing  the  protozoa  in  their  blood,  while  those  that 
become  diseased  do  not.  as  a  rule,  convey  the  affection  to  others.  In 
the  few  instances  where  they  do.  it  is  not  by  contact,  but  indirectly 
by  means  of  the  progeny  of  the  ticks  from  these  diseased  animals. 
Infection  is  not  transmitted  by  the  air,  urine,  saliva,  manure,  or  by 
anv  other  natural  manner  than  bv  cattle  ticks. 


TEXAS    FKVKR   AND   ITS   PREVENTION.  7 

HISTORY    AND    DISTRIBUTION. 

The  place  of  origin  of  this  disease  is  unknown,  but  it  has  certainly 
existed  for  centuries  in  some  countries  of  Europe,  among  which  may 
be  mentioned  southern  France.  Italy.  Turkey,  and  along  the  Danube 
River  in  Koumania.  It  is  also  prevalent  in  West  Indies,  Mexico, 
Central  America,  South  America,  Australia,  North  Africa.  East 
Africa,  South  Africa,  Ireland.  Finland,  southern  Russia,  China, 
Japan,  Java,  Borneo,  and  the  Philippine  Islands. 

It  was  probably  introduced  into  the  United  States  with  the  impor- 
tations of  cattle  by  the  Spaniards  during  the  early  colonization  of 
Mexico  and  southern  United  States. 

The  disease  caused  continual  losses  year  after  year  during  the  early 
history  of  our  country.  In  spite  of  this  fact,  it  seems  to  have  been 
described  first  by  Dr.  J.  Pease  toward  the  close  of  the  eighteenth  cen- 


!•'!<;.   1. — Itoimdary  line  of  tin-  district   infected  with  Texas  fever. 

tury.  At  that  time  a  very  severe  outbreak  of  the  disease  occurred  in 
Lancaster  County.  Pa.,  and  Pease,  after  investigating  the  conditions, 
claimed  it  to  have  been  due  directly  to  the  shipment  of  some  North 
Carolina  cattle  into  the  State. 

Experience  soon  showed  that  the  invariable  result  following  the 
transportation  of  Southern  cattle  into  the  Northern  States  was  the 
death  of  all  Northern  cattle  along  the  roads  and  on  the  pastures  over 
which  the  Southern  cattle  had  traveled,  although  the  latter  animals 
remained  perfectly  healthy.  In  the  same  way  Northern  cattle  taken 
South  were  almost  invariably  attacked  with  the  malady. 

In  18(>S  Texas  cattle  shipped  north  into  the  States  of  Illinois  and 
Indiana  earlv  in  the  summer  caused  enormous  losses,  and  cattle 


8  BUREAU  OF  ANIMAL  INDUSTRY. 

shipped  from  these  States  to  the  Eastern  markets  died  during  trans- 
portation.  These  great  losses  prompted  the  study  of  the  disease  by 
many  scientific  men.  whose  investigations  soon  established  the  great 
danger  of  allowing  Southern  rattle  to  pass  into  the  Northern  States 
during  hot  weather,  and  finally  resulted  in  1885  in  the  location  of  the 
infected  district  and  the  establishment  of  the  Texas  fever  quarantine 
line  in  185)1  by  Dr.  I).  E.  Salmon,  which  have  been  the  most  im- 
portant steps  yet  taken  toward  controlling  the  great  losses  from  the 
disease. 

Smith  was  the  first  (1889)  to  recognize  and  describe  as  protozoa 
the  intracorpuscular  parasites  which  are  the  direct  causative 
agents  of  the  disease,  although  Babes  had  previously  diagnosed  them 
as  bacteria  (Hematococcus)  for  Starcovici.  who  found  them  in  the 
blood  of  Roumanian  cattle  in  1888.  In  1889  and  1890  Kilborne,  by 
conclusive  field  experiments  suggested  by  Salmon,  proved  the  pres- 
ence of  the  cattle  tick  to  be  essential  in  the  transmission  of  the  dis- 
ease. It  is  of  interest  to  note  that  this  was  the  first  experimental 
proof  furnished  on  the  subject  of  diseases  borne  by  insects,  or  diseases 
that  can  be  carried  from  one  animal  to  another  only  by  an  inter- 
mediary host.  This  mode  of  transmitting  infections  has  since  lx>- 
come  quite  familiar  to  the  public  by  the  discovery  that  certain  species 
of  mosquitoes  spread  malaria  and  yellow  fever  to  man. 

It  was  suggested  by  the  experiments  of  the  Bureau  of  Animal 
Industry  in  189-2  and  1898  that,  through  the  production  of  a  mild, 
nonfatal  attack  of  Texas  fever  in  Northern  cattle,  a  very  consider- 
able amount  of  protection  is  afforded  against  the  disease  when  these 
cattle  are  subsequently  exposed  to  the  infection  on  tick-infested  pas- 
tures. The  methods  advanced  for  producing  such  a  mild,  nonfatal 
attack  were  (1)  the  artificial  inoculation,  either  into  a  vein  or  under 
the  skm  of  susceptible  animals  during  the  fall  or  winter,  of  defibri- 
nated  blood  from  an  immune  cow;  or  ('2)  the  less  certain  way.  con- 
sisting of  the  exposure  of  the  nonimmune  animal  to  ticks  by  confining 
the  animal  to  an  inclosed  pasture  after  scattering  ripe  egg-laving 
ticks  over  the  grass. 

From  1895  to  1897  additional  experiments  were  conducted  by  the 
Bureau  with  the  object  of  further  demonstrating  the  possibility  of 
immunizing  cattle  against  Texas  fever  by  the  use  of  blood  obtained 
from  Southern  cattle:  and  exj>eriments  with  a  similar  object  in 
view  were  likewise1  instigated  and  perfected  al>out  this  time  at  the 
experiment  stations  of  Missouri.  Texas.  Mississippi,  and  Louisiana, 
and  by  the  Australian  Government,  with  most  excellent  results. 
Later  experiments  with  the  disease  have  lx>en  performed  principally 
with  the  view  of  obtaining  a  satisfactory  chemical  solution  in  which 
to  dip  tick-infested  cattle  for  the  purpose  of  destroying  these  para- 


TEXAS  FEVER  AND  ITS  PREVENTION.  9 

sites,  and  of  developing  some  methods  that  may  l>e  easily  carried  out 
for  freeing  fields,  farms,  and  counties  of  the  cattle  tick. 


CAUSK    OF    TIIK    DISEASE. 


The  primary  or  direct  cause  of  Texas  fever  is  the  microparasite 
Piroplasma  bigeminum,  Ix'longing  to  the  lowest  form  of  animal  life, 
the  protozoa.  This  minute  parasite  is  found  in  the  blood  (PI.  3, 
fig.  5)  in  every  case  of  Texas  fever;  and  by  inoculating  blood  con- 
taining it  into  susceptible  cattle,  the  disease  can  be  invariably  trans- 
mitted, thus  proving  its  direct  causative  effect  in  the  production  of 
the  malady.  After  gaining  the  circulation  the  piroplasma  under- 
goes several  stages  of  development  which  can  be  studied  by  examining 
carefully  prepared  fresh  preparations  of  the  infected  blood  under  the 
microscope  for  several  successive  days.  In  the  first  stage  the  parasite 
is  inside  the  red  blood  cell  near  its  margin  and  is  nonmotile  and  pale, 
making  it  difficult  to  distinguish  in  the  unstained  preparations.  This 
stage  is  principally  seen  in  the  chronic  type  of  the  disease  in  which 
from  5  to  50  per  cent  of  the  red  blood  cells  are  invaded.  This  single 
body  later  divides  incompletely  into  two  small  roundish  bodies 
which  are  partially  connected  by  a  narrow  intervening  strand,  and 
this  form  may  remain  in  the  blood  for  several  days  at  least.  Some- 
times four,  five,  or  even  six  parasites  may  lx>  observed  in  one  blood  cell. 
In  the  next  stage  the  minute  double  rounded  bodies  Income  enlarged 
and  spindle-shaped.  They  probably  remain  attached,  however,  as 
in  stained  preparations  a  minute  delicate  filament  may  frequently 
be  made  out  connecting  them.  The  two  bodies  enlarge  uniformly  and 
assume  a  pear-shaped  appearance.  It  is  this  stage  of  the  life  cycle 
which  is  seen  in  the  acute  form  of  the  disease,  and  from  one-half  of 
i  to  2  per  cent  of  the  red  cells  are  usually  invaded — rarely  as  many  as 
10  per  cent.  The  parasites  at  this  time  occupy  nearly  one-fourth 
of  the  body  of  the  red  blood  cells  and.  as  can  lx>  readily  understood, 
exert  a  detrimental  influence  upon  them.  Their  periphery  Incomes 
shriveled  or  crumpled,  and  the  blood  cells  finally  break  up.  liberating 
the  piroplasma,  which  may  be  observed  as  free  bodies  in  the  circula- 
tion— most  frequently  in  the  kidneys.  The  stage  of  reproduction  or 
multiplication  of  this  protozoa  has  never  l>een  observed  in  this  lalwra- 
tory.  but  that  it  does  occur  is  proved  by  tht»  fact  that  inoculation  of 
a  small  quantity  of  virulent  blood  into  susceptible  animals  will  give 
rise  to  the  disease  with  myriads  of  parasites  in  the  blood.  Hunt, 
of  Queensland,  states  that  reproduction  occurs  by  the  development  of 
the  protozoa  into  crescentic  or  spheroidal  Ixnlies  which  burst  and  lib- 
erate the  young  forms  which  they  contain.  The  natural  path  of 
entrance  of  these  protozoa,  however,  is  by  one  channel  only,  namely, 
through  the  bite  of  the  cattle  tick.  A  knowledge  of  the  habits  and  life 
101)70— No.  78— 00  M 


10  BUREAU  OF  ANIMAL  INDUSTRY. 

history  of  the  latter  is  extremely  important  in  controlling  the  disease, 
Ix'cause  without  this  tick  Texas  fever  would»lx»  unknown. 

LIFE    HISTORY    OF    THE    CATTLE    TICK    AXI)    THE    PART    PLAYED    BY    IT    IN 

CING  TEXAS    FEVER. 


Ill  stating  the  interesting  and  important  life  history  of  this  tick, 
Ave  will  start  at  the  point  where  the  fully  developed  and  fertilized 
female,  being  engorged  with  blood  and  ready  to  lay  her  eggs,  loosens 
her  hold  on  the  lx>vine  animal  and  drops  to  the  ground.  I'pon  reach- 
ing the  ground  she  may  lie  quietly  for  several  days  Ix'fore  depositing 
her  eggs,  which  may  consume  from  four  to  eight  days  in  summer  and 
two  weeks  or  even  longer  in  the  fall.  The  nunilxn*  of  eggs  laid  by  a 
fully  developed  female  varies  from  1.500  to  3.000.  while  the  immature 
females  also  lay  eggs,  but  in  much  smaller  nunilx»rs.  After  laying  is 
finished  the  female  is  small  and  shriveled  up  and,  having  fulfilled  her 
mission,  soon  dies  (PI.  3,  fig.  3).  The  eggs,  which  are  light  brown 
and  waxy  in  appearance,  proceed  to  develop  the  larva*,  or  seed 
ticks,  the  time  required  for  which  varies  from  thirteen  days  to  six 
weeks,  depending  on  the  conditions  of  temperature,  moisture,  soil. 
etc.  These  eggs,  however,  are  very  tenacious  of  life,  and  under 
unfavorable  conditions  may  remain  dormant  for  several  months  — 
from  late  fall  to  early  spring. 

The  larva1,  or  seed  ticks,  are  minute  six-legged  parasites  of  a 
brownish  waxy  color,  and  about  ^  of  an  inch  in  size  (PI.  3.  fig.  2). 
They  crawl  quite  actively  about  on  the  ground  and  among  leaves, 
bunching  in  large  numbers  upon  grass  blades,  shrubs,  weeds,  and 
fence  posts,  to  await  an  opportunity  for  attachment  to  their  passing 
host.  In  case  no  cattle  or  horses  are  present,  the  parasitism  is  so  per- 
fect that  no  further  development  occurs,  and  death  finally  results. 
It  is  known,  however,  that  these  larval  forms  can  live  for  three  or 
four  months  on  the  ground  in  warm  weath.M*  independent  of  their 
host,  and  from  late  September  until  Apr'l  during  an  open  winter. 
When  they  find  cattle,  however,  they  cnn  iip  the  legs  and  attach 
themselves  to  the  soft  skin  inside  the  thigi.  ar.d  Hanks,  on  the  es- 
cutcheon. along  the  Ix'lly  and  brisket,  around  the  root  of  the  tail,  and 
inside  the  forelegs  (PI.  3.  fig.  4).  They  obtain  their  nourishment 
by  drawing  blood  from  the  host,  and  can  cause  the  fever  at  this  stage, 
although  so  small  as  scarcely  to  In-  detected  by  the  naked  eye.  After 
being  on  the  animal  about  one  week  the  seed  tick  casts  its  covering 
(molts)  and  appears  as  the  eight-legged  nymph  stage  of  the  parasite, 
having  added  one  pair  of  legs  posteriorly.  During  the  nymphal 
stage  the  sexual  organs  develop,  and  at  the  second  molting  from  the 
nymphal  to  the  adult  stage  the  sexual  organs  are  complete.  The 
male  and  female  at  this  stage  are  about  the  same  size,  as  the  female 


TEXAS    FKVKH    AND    ITS    PKKVEXTJON.  11 

does  not  lx;come  very  large  until  after  she  Incomes  fertilized,  which 
occurs  about  two  weeks  after  the  six-legged  seed  tick  reaches  its  host, 
or  shortly  after  the  second  molting  (PI.  3,  figs.  7  and  0).  After  in- 
tercourse with  the  male  the  female  slowly  enlarges  for  six  to  twenty 
days  in  summer,  and  then  rapidly  increases  in  size  in  the  course  of  a 
day  or  two  before  dropping  off  the  animal.  In  fall  and  winter  de- 
velopment occurs  more  slowly,  the  tick  not  falling  off  for  six  weeks  or 
more.  After  reaching  the  ground  the  female  soon  commences  to  de- 
posit eggs,  thus  completing  the  life  cycle,  which  requires  from 
six  to  ten  weeks  in  warm  weather,  or  a  much  longer  period  during  the 
cold  season. 

Although  young  ticks  are  very  active,  neither  they  nor  the  adult 
ticks  are  capable  of  crawling  very  far.  but  they  may  l>e  transported 
long  distances  by  animals,  by  rains,  by  winds-,  cattle  cars,  hides,  and 
on  the  clothing  of  man.  Hence  the  constant  danger  that  tick-free 
pastures  below  the  line  may  become  infested  with  ticks  at  any  time. 

The  tick  causes  more  or  less  irritation  of  the  skin  at  the  point  where 
it  attaches,  and  it  has  been  suggested  that  it  injects  some  poisonous 
substance  into  its  bites  along  with  the  Piroplaxnm  bif/em'tnitm.  which 
reduces  the  vitality  of  the  tissues  and  enables  the  protozoan  to  multi- 
ply, and  to  get  a  start,  so  to  speak.  This  is  considered  to  IK?  the  case, 
because  it  has  frequently  been  experimentally  attempted  to  reproduce 
Texas  fever  by  inoculating  susceptible  animals  both  into  the  vein  and 
under  the  skin  with  salt  solution  emulsions  of  ticks  ground  up  in  a 
mortar,  and  also  by  feeding  ticks,  but  uniformly  without  success. 
However,  it  is  probable  that  the  protozoan  passes  a  resting  stage  of  its 
life  cycle  in  the  body  of  the  ticks,  which  would  explain  these  failures. 

The  great  length  of  time  required  for  the  appearance  of  the  disease1 
in  Northern  cattle  after  the  passage  of  tick-bearing  cattle  through  the 
country  (thirteeen  to  ninety  days)  can  easily  IM>  accounted  for  by  the 
life  history  of  the  tick.  It  is  necessary  before  the  disease  appears  for 
the  fully  developed  fertilized  female  to  drop  off  the  Southern  cattle 
and  deposit  the  eggs,  ami  for  them  to  hatch  into  the  six-legged  larvje. 
These  must  then  crawl  up  on  the  Northern  cattle  and  insert  the  micro- 
parasites  they  carry  through  the  bites  made  in  the  skin  in  procuring 
their  nourishment.  Texas  fever  follows.  It  will  thus  |H«  seen  that 
these  females  transmit  the  infection  through  their  eggs  to  their 
progeny,  and  the  latter  have  the  power  to  infect  any  sus<rptible 
animal  to  which  they  attach.  The  disease  therefore  is  not  conveyed 
by  the  same  ticks  which  take  up  the  infected  blood,  but  only  through 
the  generation  descending  from  them. 

The  first  experiment  performed  by  Kilborne  in  proving  the  "  tick 
theory  "  consisted  in  placing  four  North  Carolina  tick-infested  cattle 
in  a  special  inclosure.  and  at  various  times  thereafter  placing  13  sus- 


1*2  BUKKAU    OF    ANIMAL    INDUSTRY. 

eeptible  animals  in  the  same  Hold;  of  these  10  died  of  the  disease, 
•J  recovered,  and  1  was  unaffected.  In.  the  second  experiment  all 
ticks  were  carefully  picked  by  hand  from  3  North  Carolina  cattle 
which  were  placed  in  a  second  noninfected  Held.  Five  susceptible 
cattle  were  then  placed  in  the  field  with  these  tick-free  North  Caro- 
lina cattle  and  all  remained  perfectly  healthy.  Finally,  in  1S<)0. 
•young:  ticks,  hatched  and  raised  in  the  laboratory,  were  placed  on  4 
susceptible  animals  and  produced  Texas  fever  in  every  case,  thereby 
proving:  that  the  tick  was  responsible  for  the  disease.  Other  experi- 
ments have  l>een  performed  by  feeding:  virulent  materials,  by  expos- 
ing: cattle  to  the  urine,  manure,  and  nasal  secretion  of  sick  animals, 
and  to  the  blood  and  viscera  of  cattle  dead  of  Texas  fever,  but  always 
with  negative  results,  thus  eliminating:  these  as  the  causative  factors, 
and  furnishing;  indirect  evidence  substantiating:  the  "  tick  theory."' 

HOW   TO   DISTINGUISH    IIAKMLKSS   TICKS   FOUND   ON    CATTLE    FKOM    TEXAS- 
FEVER    TICKS. 

The  Texas-fever  tick,  also  called  the  cattle  or  cow  tick,  is  continu- 
ally confused  with  a  number  of  other  ticks  occasionally  found  on 
cattle,  but,  so  far  as  concerns  the  transmission  of  Texas  fever,  en- 
tirely harmless  to  them.  It  is  this  lack  of  identification  and  the 
inability  of  many  cattle  owners  to  distinguish  l>etween  these  various 
ticks  that  have  caused  so  many  diverse  opinions  regarding  the  impor- 
tant part  played  by  the  Texas-fever  tick  in  transmitting:  Texas  fever. 
In  order  to  differentiate  between  the  ticks  that  may  be  found  on 
cattle,  a  brief  description  of  the  upper  surface  of  the  maturing  or 
adult  female  of  each  is  here  given,  together  with  illustrations  of 
this  view  of  the  ticks,  natural  sixe.  and  also  magnified  four  diameters. 
It  was  not  thought  necessary  to  furnish  the  stockman  with  a  descrip- 
tion of  the  male  and  immature  female  ticks  at  this  time,  inasmuch 
as  these  ticks  are  much  smaller  in  sixe.  and  therefore  it  is  more  diffi- 
cult to  recognize  the  various  differences  between  these  forms  of  the 
different  species  by  means  of  the  naked  eye.  Moreover,  it  is  usually 
possible  to  secure  a  maturing:  female  in  those  instances  where  a  diag- 
nosis is  desired,  and  at  this  stage  of  development  ticks  possess  certain 
characteristic  features  or  markings  which  should  cause  then* to 
!M>  classified  readily  as  harmful  or  harmless  even  by  superficial 
examination.  Ticks  said  to  IM>  Texas- fever  ticks  have  lx>en  reported 
by  some  stockmen  as  infesting  susceptible  cattle  without  producing 
Texas  fever,  and  by  others  mature  ticks,  presumed  to  be  Texas- 
fever  ticks,  have  l>een  found  on  uncultivated  land  and  in  woods 
where  cattle  have  never  graxed.  These  statements  have  been  fre- 
quently advanced  in  order  to  refute  the  experiments  already  men- 
tioned as.  to  the  essential  part  played  by  the  Texas-fever  tick  in  caus- 


TEXAS   FKVER    AND    ITS   PREVENTION.  13 

ing  Texas  fever.  If  fever  ticks  have  Iwen  found  on  nonimmune 
cattle  without  producing  Texas  fever,  the  explanation  is  that  these 
particular  ticks  were  probably  noninfectious,  which  in  rare  cases 
is  seen,  as  described  in  section  on  *'  Some  objections  to  the  role  of 
ticks  as  carriers  of  Texas  fever,  with  explanations."  On  the  other 
hand,  it  has  very  frequently  happened  that  an  examination  by  one 
familiar  with  the  characteristics  of  ticks  has  shown  that  those  found 
on  such  cattle  and  supposed  to  have  been  fever  ticks  belong  to  another 
species  that  is  entirely  harmless  as  regards  transmitting  Texas  fever. 

All  the  investigations  regarding  the  life  history  of  the  Texas-fever 
tick  show  that  although  the  young,  or  larva-,  may  live  for  a  long  time 
on  the  ground  without  a  host,  they  can  not  mature  except  as  parasites 
on  the  bodies  of  cattle,  or,  less  frequently,  of  horses,  mules,  and  asses. 
And  statements  claiming  that  the  adult  ticks  of  this  species  have  been 
observed  to  develop  in  localities  where  their  absolutely  necessary  hosts 
have  never  been  are  erroneous,  resulting  from  the  confusion  caused  by 
the  similarity  in  appearance  of  the  cattle  tick  to  the  harmless  ticks. 
It  therefore  becomes  merely  a  question  of  recognition,  and  the  follow- 
ing short  descriptions,  taken  principally  from  Salmon  &  Stiles  's  paper 
on  *"  Cattle  ticks,"  are  furnished  to  assist  in  recognizing  the  fever  tick 
and  in  distinguishing  it  from  others  that  may  l>e  observed  on  cattle. 

There  are  eight  species  of  ticks  which  have  been  found  on  cattle  in 
this  country,  but  the  first  six  mentioned  are  by  far  the  most  common. 
They  all  show  the  same  successive  stages  of  development,  namely. 
eggs,  larva1  or  seed  ticks,  nymphs,  and  adult  male  and  female  ticks. 
Those  parts  of  the  adult  female  tick  which  will  l>e  descriU'd  l>elow 
are  the  head  and  adjacent  shield  —  which  together  have  erroneously 
been  termed  the  head  parts  —  and  the  back  of  the  body,  since  these 
portions  of  the  parasite  furnish  features  which  to  the  naked  eye  are 
the  most  readily  distinguished  by  cattle  owners.  Much  stress  can 
not  be  laid  upon  the  color  of  these  various  ticks,  as  it  changes  con- 
siderably with  age.  In  the  adult  stage  they  all  have  four  pail's  of 
legs,  varying  in  length  and  slenderness  according  to  the  sj>ecies, 
but  these  differences  are  not  sullicient  to  separate  one  species  from 
another. 


(iniiulatiix  <  7V.rr/.s'  fcrrr.  or  cnttlr.  tick).  —  IMato  1.  figure  1.1.  shows 
tin1  natural  size  of  an  adult  female  Texas-fever  tirk.  whose  characteristic 
markings  are  better  brought  out  in  figure  1.  magnified  four  times."  This  tick  may 
be  readily  distinguished  from  the  other  seven  ticks  by  the  small  si  7.0  and  the 
color  of  the  head  and  shield,  the  so-called  head  parts,  whose  lateral  borders 
are  straighter  and  more  parallel,  as  shown  in  figure  1b.  These  head  parts  are 
short  and  relatively  broad  and  dark  reddish  brown  or  chestnut  brown  in 

"  Tn  each  of  Plates  1  and  '2  there  an1  shown  (It  the  natural-sized  mature 
female  tick.  (-)  this  tick  magnified  four  times,  and  ('.})  the  head  and  shield  of 
the  same  enlarged  ten  to  fifteen  times. 


14  BUREAU  OF  ANIMAL  INDUSTRY. 

color,  appeal-in;:  MS  a  convex  plate  <>n  the  median  Hue  at  the  fore  end  of  the 
tick.  The  Ixxly  is  oblong  oval  in  slm]»e  and  may  reach  i  inch  in  length.  The 
color  varies  from  a  dull  yellow  to  an  olive  brown  ;  often  it  is  mottled  with 
irregular  areas  of  yellow  and  brown  or  streaked  with  wavy  lines  of  these 
colors.  Two  grooves  or  indentations  are  seen  running  from  the  front  to  the 
rear  on  the  skin  of  the  back,  which  liecome  almost,  if  not  entirely,  effaced  at 
about  the  middle  of  the  body.  Another  groove  is  seen  l»etween  these  two  grooves 
in  the  posterior  half  of  the  ltody.  These  grooves  are  caused  by  the  contraction 
of  the  mnsoles  of  the  l»ody  and  therefore  vary  considerably,  entirely  di sap] tear- 
ing when  the  tick  is  full  of  blood.  They  are  very  distinct  when  the  ticks  have 
Iteen  removed  from  cattle  several  days.  The  four  pairs  of  legs  are  brown, 
moderately  long,  and  very  slender.  This  tick  is  found  principally  on  cattle, 
less  frequently  on  horses,  mules,  and  asses,  and  in  one  case  it  was  found  on  a 
deer.  The  Federal  quarantine  line  indicates  the  northern  boundary  of  the  sec- 
tion of  the  United  States  infested  with  fever  ticks. 

Ifndex  ricimix  (cantor-bean  tick). — The  body  of  this  tfck  (IM.  1.  tigs.  '2  and  lia) 
resembles  in  shaj>e  that  of  an  eggplant,  and  it  takes  its  name  from  its  similarity 
to  the  Itean  of  the  castor-oil  plant.  It  is  lead-colored,  with  a  variegated  mixture 
of  yellowish  red.  brown,  or  gray.  The  Itody  contains  two  anterior  groove's  that 
slightly  diverge  from  each  other,  and  three  posterior  grooves,  the  middle  one  of 
which  is  straight,  while  the  other  two  are  curved  outward.  The  mature  female 
is  from  1  to  fa  inch  long  and  lias  four  pairs  of  dark-brown  thin  legs.  The 
bead  and  adjacent  shield  are  a  shiny  dark  brown  or  a  chestnut  brown,  the  latter 
INtrtion  lieing  five-sided,  like  a  jKMitagon  (fig.  lib),  with  lateral  liorders  prominent 
and  rear  angle  rounded.  Two  stout  and  well-develoiK.nl  feelers  (palpi)  may  be 
seen  extending  outward  on  each  side  of  the  head.  This  tick  has  been  collected 
from  sheep,  cattle,  goats,  horses,  deer,  dogs,  cats,  foxes,  rabbits,  birds,  man,  and 
a  few  other  animals.  It  was  one  of  the  first  ticks  studied,  and  has  a  very  wide 
distribution  in  the  United  States. 

Dcrmacentor  rcticiilattix  (net  tick). — The  body  of  the  adult  female  tick  is 
oblong  oval.  jj  inch  long,  and  of  a  deep  brown  or  slate  color  (IM.  1.  figs.  3  and 
3a).  It  has  four  pairs  of  brown  legs  of  moderate  length.  The  skin  of  the 
back  and  head  is  covered  with  fine  ]>oints.  or  punctations.  which  almost  dis- 
appear at  this  stage.  Besides  the  grooves  that  are  located  like  those  in  the 
cattle  tick,  there  is  a  marginal  groove  extending  around  the  liody  just  inside 
the  border.  There  are  also  eleven  small  indentations  ( festoons  i  arranged 
aliout  the  ]M»sterior  margin  of  the  liody.  These  festoons  and  grooves  become 
shallow  or  effaced  in  the  adult  stage.  The  shield  |>ortion  of  the  head  [tarts 
has  a  silvery  white  metallic  rust  extending  along  the  two  sides  and  posterior 
portion  (fig.  3b ).  It  may  have  a  rose  or  greenish  tinge.  The  head  is  larger 
than  that  of  the  cattle  tick.  The  net  tick  has  been  found  on  man.  rattle, 
horses,  sheep,  and  deer;  and  in  this  country  it  seems  to  lie  most  common  in 
the  West,  especially  in  California.  Texas,  and  New  Mexico. 

Dcnuaccntor  elect  HX  (American  doy  tick:  nl*o  called  irood  tick). — This  tick 
( IM.  1.  figs.  4  and  4a)  resembles  the  net  tick  (Itennacentor  reticulatum  so 
closely  that  a  band  lens  must  be  used  to  distinguish  lietween  them.  However, 
it  can  be  readily  known  from  the  Texas-fever  tick  by  the  fact  that  the  so-ralb-d 
head  parts  are  longer  and  broader  (fig.  4b).  Here  there  is  also  a  yellowish 
white  rust  in  the  |tosterior  ]tortion  which  extends  anteriorly  along  each  side 
as  two  bright,  iridewent  lines  separated  by  a  central  brownish  area.  The 
Itody  is  oblong  oval  in  sha]M>  and  measures  as  much  as  ?,  inch  in  length. 
The  skin  of  the  back  contains  grooves  like  those  found  in  cattle  ticks,  and.  in 
addition,  another  groove  extending  around  just  inside  the  margin,  together 
with  eleven  smaller  grooves  (festoons)  on  the  posterior  Itorder.  These  lines, 


TEXAS  FEVER  AND  ITS  PREVENTION.  15 

so  distinct  in  the  young  female,  become  shallow  at  maturity.  This  tick  has 
been  found  on  man,  cattle,  dogs,  horses,  rabbits,  and  panthers,  and  has  been 
collected  in  woods  and  on  uncultivated  lands  in  many  sections  of  this  country, 
especially  in  eastern  United  States. 

Amblytymimj,  (niicriciniinn  (Lone  Ntar  tick). — As  is  indicated  by  figures  1  and 
la  of  Plate  2.  the  body  of  this  tick  is  oblong  oval  and  of  a  yellowish  gray  »r 
brown  color.  The  skin  is  rough  and  puckered  unless  the  body  is  full  of  blood. 
The  reddish  brown  area  ;it  the  front  of  the  tick  is  contused  of  the  head  and 
head  shield.  The  latter  extends  backward  a  short  distance  to  form  a^  triangle, 
in  the  aj»ex  of  which  is  a  white  or  metallic  yellow  sjiot  from  which  it  derives 
its  name  "Lone  Star"  (fig.  lb).  The  mature  female  may  reach  i  inch  in 
length  and  has  four  pairs  of  long  thin  legs.  This  tick  has  been  found  on  cattle, 
dogs,  horses,  sheep,  ami  man.  and  is  very  widely  distributed  in  the  United 
States. 

Oriiithodnnnf  inf't/nini  (car  tick). — As  will  be  observed  from  figures  '2.  and 
L'a,  Plate  '2,  the  shape  of  this  tick  is  similar  to  that  of  the  Ixnly  of  a  violin.  It 
is  nearly  twice  as  long  as  broad,  rounded  at  Inrth  ends,  narrower  behind  than 
in  front,  and  slightly  constricted  in  the  middle.  In  color  it  varies  from  gray 
or  brown  to  violet,  and  has  two  grooves  behind  the  head,  with  a  middle  one  lii 
the  posterior  i>ortioii.  On  the  skin  of  the  back  an*  numerous  minute  spines,  or 
stiff  hairs.  The  adult  females  are  from  i  to  j|  inch  in  length,  and  have  four 
pairs  of  long  stout  legs.  The  anterior  ]»ortion  of  the  tick  is  curved  downward 
to  form  a  cover  for  the  very  small  and  short  head,  which  can  only  l>e  seen  from 
the  under  side  of  the  tick.  The  feelers  (palpi)  and  l>eak,  however,  stick  out 
from  under  the  front  part  of  the  body  and  can  l>e  seen  from  alwve  (fig.  2b). 
This  tick  is  found  in  the  ears  of  cattle,  horses,  mules,  asses,  and  other  animals 
in  the  South  and  West. 

Argus  miniatim  (chicken  tick). — In  shajn1  and  apjtearance  this  tick  is  like  an 
enlarged  bedbug,  and  is  of  a  uniform  reddish  brown  color,  with  four  pairs  of 
lighter  colored  legs.  The  skin  is  wrinkled  and  contains  very  short  and  minute 
hairs.  On  the  top  as  well  as  the  lx>ttom  of  the  tick  are  numerous  bright  pits 
or  cavities  with  raised  borders  (PI.  -.  figs.  .'J  and  .'la).  These  vary  in  size, 
are  arranged  in  rows  radiating  from  the  center  more  or  less  uniformly,  and  are 
usually  symmetrical  on  each  side.  It  is  about  g  inch  in  size  when  mature.  The 
head  is  so  completely  covered  by  the  body  that  it  can  not  be  seen  from  the  back 
(fig.  .'{b).  This  tick  has  been  observed  on  cattle  once  only,  but  is  frequently 
found  on  chickens,  turkeys,  and  other  birds  in  the  South. 

fj-odcx  }n:r(if/(niiix  (Kimti>caii  <lo<i  tick\. — The  body  of  this  tick  is  oval  in 
shape  :yid  of  an  ashy  color  (PI.  li.  tigs.  4  and  4a).  The  grooves  on  the  back 
are  united  in  an  arch  in  front  and  diverge  in  the  jiosterlor  |Mirtion  of  the  body. 
The  four  pairs  of  legs  are  longer,  thicker,  and  stronger  than  those  of  the  cattle 
tick.  The  head  and  shield  are  brown-mi  in  color  and  similar  in  shai»e  to  those  of 
the  castor-bean  tick,  but  less  oval  and  rather  more  lo/.enge-sha|»ed.  with  more 
acute  lateral  .ingles  and  narrower  |M»sterior  angle  (fig.  4b).  The  palpi,  or  feel- 
ers, are  longer  and  more  prominent  than  in  the  cattle  tick,  but  not  so  long  as  in 
the  castor-bean  tick.  This  dog  tick  has  IKHMI  collected  from  dogs,  cattle,  sheep, 
foxes,  rabbits,  squirrels,  gophers,  cats,  birds,  man.  and  other  hosts  in  eastern 
United  States. 

SOMK    OBJECTIONS   IX)    TIIK    ROI.E    OF    TICKS    AS    CAKKIKRS   OF    TF.XAS    FF.YF.R. 

WITH     EXPLANATION'S. 

7V.M.v  fci'cr  in  antmtiln  ap-pareiiily  not  infested  irith  tick*. — One 
objection  that  has  been  advanced  against  the  fact  that  the  cattle 
tick  is  a  carrier  of  Texas  fever  is  that  cattle  are  sometimes  found  to 


16  BUREAU  OF  ANIMAL  INDUSTRY. 

be  suffering  with  the  disease  without  showing  the  presence  of  the 
ticks  on  their  Inxlies.  This  condition,  in  case  of  Southern  cattle, 
may  be  explained  on  the  hypothesis  that  the  animal  already  had  its 
blood  infected  with  the  microparasites  and  under  normal  conditions 
was  immune  from  Texas  fever;  however,  as  a  result  of  lowered 
vitality  caused  by  some  other  disease,  or  by  exposure,  privation, 
injury,  rough  handling,  etc.,  this  immunity  has  become  reduced  and 
finally  overcome,  and  the  parasite  of  Texas  fever,  dealing  now  with 
an  impoverished  condition  of  the  animal,  succeeds  in  producing 
Texas  fever.  Since  the  experiments  of  this  Bureau  show  that  the 
blood  of  an  immune  animal  may  contain  this  microparasite  for  at 
least  thirteen  years  after  removal  from  all  sources  of  infection,  it 
would  appear  that  this  recurrence  of  disease  in  immune  animals 
placed  under  adverse  conditions  could  occur  at  almost  any  period  of 
their  lives,  and  may  be  termed  a  relapse.  Thus  it  has  IKHMI  fre- 
quently noted  that  Southern  cattle,  born  and  raised  in  infected  pas- 
tures but  later  freed  of  ticks  and  placed  on  noninfected  soil,  have 
died  of  Texas  fever  when  their  health  was  so  weakened  as  to  permit 
the  parasites  already  infecting  the  blood  to  overcome  the  natural 
resistance  of  the  body,  and  produce  the  disease. 

Again,  in  certain  dipping  experiments  where  the  animals  had  IHHMI 
roughly  handled  and  unduly  exposed  after  having  been  dipped  in  :i 
severely  irritating  solution,  a  few  deaths  occurred  from  Texas  fever 
among  cattle  which  were  known  previously  to  have  l>een  immune — 
tick-infested  Southern  animals — but  whose  vitality  had  been  reduced 
through  these  extraordinary  conditions. 

On  the  other  hand,  when  this  disease  is  observed  in  Northern  ani- 
mals, the  young  seed  ticks  may  be  so  small  and  so  few  in  number  as 
to  be  passed  readily  by  even  a  careful  examination,  yet  numerous 
enough  to  cause  the  affection.  In  such  cases  the  proof  will  IM>  found 
either  by  prolonged  search  or  in  the  fact  that  other  animals  subse- 
quently take  the  disease  with  larger  ticks  apparent  on  the  skin. 

Southern  cuttle  infected  irit/i  ferer  tick*  mat/  die  of  Te,r((x  ferer.- 
When  cows  born  and  raised  in  the  South  die  of  Texas  fever,  it  is 
proof  that  such  cattle  never  came  in  contact  with  infected  cattle 
ticks  before,  or  that  they  were  raised  on  tick-free  pastures,  or  that 
they  l>elong  to  those  cases  of  immune  Southern  cattle  which  lose 
their  immunity  when  subjected  to  adverse  or  extraordinary  condi- 
tions, such  as  those  mentioned  above.  Otherwise  they  would  have 
been  unsusceptible  and  would  not  have  developed  Texas  fever. 
Southern  cattle,  when  raised  and  kept  in  districts  free  from  cattle 
ticks,  fail  to  secure  the  natural  immunity  induced  by  gradual  and 
constant  tick  infestation  from  birth,  and  they  are  just  as  susceptible 
to  the  disease  as  are  Northern  animals,  ruder  certain  conditions, 
as  when  living  on  horses,  mules,  etc.,  fever  ticks  lose  their  infectious- 


DESCRIPTION  OF  PLATES. 

PLATK  1. 

Fi«;.  1.  Mature  female  cattle  tick  (  X  4). 

la.  Mature  female  cattle  tick  (natural  size), 

lb.  Head  and  shield  of  same  (X  15). 

2.  Mature  female  castor-I>ean  tick  (X  4). 

2a.  Mature  female  castor-bean  tick  (natural  size). 
2b.  Head  and  shield  of  same  (X  15). 

3.  Mature  female  net  tick  (X  4). 

3a.  Mature  female  net  tick  (natural  size). 
3b.  Head  and  shield  of  same  (  X  15). 

4.  Mature  female  dog,  or  wood,  tick  ( X  4). 

4a.  Mature  female  dog,  or  wood,  tick  (natural  size). 
4b.  Head  and  shield  of  same  (X  15). 

PLATE  2. 

Fni.  1.     Mature  female  Lone  Star  tick  (  X  4). 

la.  Mature  female  Lone  Star  tick  (natural  size), 
lb.   Head  and  shield  of  same  (  X  15). 

2.  Mature  female  ear  tick  (  X  4). 

2a.  Mature  female  ear  tick  (natural  size). 

2b.  Head  of  same  protruding  from  beneath  (X  15). 

3.  Mature  female  chicken  tick  ( X  4). 

3a.  Mature  female  chicken  tick  (natural  size). 
3b.  Upper  portion  of  same,  head  invisible  (X  10). 

4.  Mature  female  European  dog  tick  (  X  4). 

4a.  Mature  female  European  dog  tick  (natural  size). 
4b.  Head  and  shield  of  same  (X  15). 

PLATE  3. 

Fio.  1.  Larva  of  cattle  tick  (X  25). 

'2.  l^arva  of  cattle  tick  (natural  size). 

:i.  Mature  female  and  eggs  (natural  size). 

4.  Hide  showing  cattle  ticks  (natural  size). 

o.  Blood  cells  containing  Texas  fever  protozoa  (X  1,000), 

6.  Male  cattle  tick  (X  15). 

7.  Male  cattle  tick  (natural  size). 

8.  Young  female  cattle  tick  (  X  15). 

9.  Young  female  cattle  tick  (natural  size). 

10.  Various  stages  and  colorations  of  cattle  ticks. 


BULL.  No.  78,  B.  A.  I. 


PLATE  1 


Haiues.del. 


VARIOUS  TICKS  THAT  INFEST  CATTLE. 


BULL.  No.  78,  B.  A.  I. 


PLATE  2. 


Haines,del. 


VARIOUS  TICKS  THAT  INFEST  CATTLE. 


.  Ho«n  I.Co..Li«ta- 


BULL.  No.  78,  B.  A.  I. 


PLATE  3. 


9-* 


•        #       * 


,        »        •         *       f 


Hames.del.  A  Ho»r  »co,iitho 

TEXAS  FEVER  PROTOZOA  AND  THE  TICKS  WHICH  TRANSMIT  THEM. 


TEXAS    FEVER    AND    ITS    PREVENTION.  17 

ness,  and  when  Southern  cattle  not  previously  infested  with  any  but 
these  noninfected  ticks  come  in  contact  with  infected  ticks  they  are 
just  as  susceptible  as  cattle  raised  on  tick-free  pastures,  as  indicated 
below. 

Harmless  ticks  mistaken  for  Texas- fever  ticks. — A  very  prolific 
cause  for  argument  against  the  relation  of  ticks  to  Texas  fever  has 
been  the  confusion  which  exists  with  reference  to  the  various  sj>ecies 
of  ticks  observed  on  cattle.  Some  stockmen  have  claimed  that  ticks 
will  not  cause  Texas  fever,  because  their  experience  has  not  been 
with  the  Texas-fever  ticks,  but  with  the  species  of  ticks  described  in 
the  preceding  pages,  which  are  harmless  so  far  as  their  ability  to 
transmit  Texas  fever  is  concerned,  or  with  the  noninfected  cattle 
ticks  mentioned  below.  A  similar  experience  with  these?  harmless 
licks  upon  woodland  far  removed  from  cattle  and  confusing  them 
with  cattle  ticks  have  led  others  to  claim  that  it  would  be  impossible 
to  eradicate  the  latter  from  infested  pastures.  However,  their  life 
histories  are  not  parallel,  since  the  cattle  ticks  demand  the  blood  of 
cattle  or  equines  in  order  to  mature,  while  the  ear,  dog.  Lone  Star 
ticks,  and  others  do  not.  Thus,  if  the  fever  ticks  can  be  separated 
from  these  animals  for  a  definite  period  they  will  die  from  lack  of 
a  host. 

Susceptible  animals  having  ferer  ticks  without  Texas  fecer. — In 
rare  cases  it  has  been  observed  that  certain  Texas-fever  ticks  do  not 
contain  the  protozoan  of  Texas  fever,  and  when  such  ticks  fail  to 
produce  disease  in  susceptible  animals  some  persons  have  been  led  to 
argue  that  none  of  this  species  will  transmit  the  infection.  Texas- 
fever  ticks  without  the  virus  of  Texas  fever  in  their  bodies  are  termed 
noninfected  ticks.  They  may  have  lost  their  infectious  property  by 
living  on  a  nonsusceptible  animal,  such  as  a  horse,  mule,  ass,  or  suck- 
ing calf,  as  experiments  have  shown  that  a  generation  of  infected  ticks 
on  these  animals  will  eliminate  the  infection  from  their  bodies  and, 
when  the  next  generation  of  seed  ticks  is  placed  on  susceptible  cat- 
lie,  no  disease  is  produced.  These  ticks  will  become  reinfected,  how- 
ever, if  allowed  to  infest  Southern  cattle  containing  the  Texas-*fever 
protozoa  in  their  blood.  Noninfected  cattle  ticks  are  so  very  uncom- 
mon that  they  are  the  exception,  and  since  the  vast  majority  are 
dangerous  it  would  be  advisable  to  treat  all  cattle  ticks  as  infected  and 
capable  of  transmitting  Texas  fever  . 

Fercr  tirkx  on  other  <n>iin<tlx  in'f/nmf  j>rt><li(rin</  f//.sr</.sr. — The  rea- 
son that  Texas-fever  ticks  can  remain  on  animals  other  than  cattle 
without  producing  the  disease  is  because  these  animals  are  not  sus- 
ceptible to  Texas  fever.  Numerous  experiments  have  shown  that 
only  bovines  contract  Texas  fever,  so  it  is  not  difficult  to  understand 
why  other  hosts  can  be  infected  with  impunity. 
1CKJ7J) — No.  TS — 00  M y 


18  BURKAU    OF    ANIMAL    INDUSTRY. 

OTHER    rX.IfRlOrS   EFFECTS   OF   CATTLE   TICKS. 

Many  cattle  owners  who  have  always  IXUMI  accustomed  to  see  both 
ticks  and  tieky  cattle  on  their  farms  are  unfortunately  not  inclined 
to  attach  much  importance  to  cattle  ticks,  and,  as  a  rule,  through 
lack  of  appreciation  of  their  damaging  effects,  placidly  consider  them 
as  of  little  consequence.  That  ticks  may  be  detrimental  to  their  hosts 
in  several  ways  has  probably  not  suggested  itself  to  these  stockmen, 
who  are  most  vitally  affected,  and  it  therefore  seems  necessary  to 
emphasize  the  fact  that,  in  addition  to  their  relation  to  Texas  fever, 
they  may  also  be  injurious  to  cattle  as  external  parasites.  While 
the  power  of  transmitting  Texas  fever  is  undoubtedly  the  most  dan- 
gerous property  possessed  by  the  cattle  tick  and  is  the  principal 
causo  for  adopting  stringent  measures  in  securing  its  complete  eradi- 
cation, nevertheless  there  still  remain  other  good  reasons  for  the 
accomplishment  of  this  achievement.  These  secondary  objections  to 
the  presence  of  ticks  on  cattle  consist  in  the  physical  harm  they  do 
to  the  host  aside  from  the  production  of  the  specific  disease  of 
Texas  fever.  True,  a  few  parasites  may  remain  on  cattle  indefinitely 
without  causing  any  noticeable  effect,  but  it  is  not  uncommon  to 
notice  bovine  animals  on  pastures  with  their  hides  heavily  infested 
with  these  pests.  In  such  cases  it  can  readily  be  seen  that  the  contin- 
uous sucking  of  blood  causes  more  or  less  impoverishment  of  the 
circulation.  The  animal  must  therefore  lx»  fed  heavier  in  order  to 
meet  the  demands  of  the  parasites  in  addition  to  the  ordinary  needs 
of  the  host.  If  the  ticks  be  removed  from  the  body,  the  bites  inflicted 
are  often  distinguished  by  small  inflamed  or  reddened  areas  some- 
what swollen,  with  perforations  of  the  skin  which  may  allow  the 
entrance  of  various  kinds  of  disease  germs,  and  showing  that  more 
or  less  irritation  of  the  hide  is  produced  by  these  parasites.  This 
condition,  together  with  the  loss  of  blood,  frequently  induces  an  irri- 
table state -and  evidences  of  uneasiness  commonly  known  as  "tick 
worry."  which  results  in  the  loss  of  energy  and  other  derangements  of 
the  animal's  health.  It  may  in  some  cases  become  so  pronounced, 
especially  in  hot  weather,  that  the  animal  will  lose  flesh  in  spite  of 
good  pasturing,  thereby  reducing  the  vitality  and  rendering  it  more 
susceptible  to  the  inroads  of  disease.  Moreover,  if  the  infestation  of 
ticks  is  not  controlled,  the  cattle  may  be  so  reduced  in  condition  that 
growth  is  retarded,  and.  in  the  case  of  young  animals,  they  may  never 
l>ecome  fully  developed,  but  remain  thin.  weak,  and  stunted — a  con- 
dition that  has  been  termed  "tick  poverty" — and  easily  succumb  to 
other  diseases  as  a  result  of  lowered  vitality.  In  milch  cows  this 
debilitating  influence  of  the  numerous  ticks  is  shown  in  a  greatly 
reduce* I  milk  supply.  This  should  not  apj)ear  strange  when  it  is  con- 
sidered that  some  animals  harbor  several  thousand  of  these  blood- 


TEXAS    FEVER    AND    ITS    PREVENTION.  19 

sucking  parasites.  If  these  parasites  are  crushed,  it  will  be  found 
that  their  intestines  are  completely  filled  with  a  dark,  thick  mass  of 
blood  abstracted  from  the  animal  host  and  containing  nutriment  that 
should  go  to  the  formation  of  milk,  flesh,  and  the  laying  on  of  fat. 
In  some  rare  cases  the  large  number  of  bites  over  a  limited  area  of 
skin  may  be  followed  by  infection  with  pus-producing  organisms, 
giving  rise  to  small  abscesses  which  ma}'  terminate  in  ulcers.  Tim 
discharge  from  such  sores,  or  in  some  cases  the  mere  oozing  of  blood 
serum  through  the  incision  made  by  the  mouth  parts  of  the  ticks, 
keeps  the  hair  moist  and  matted  together,  and  the  laying  and  hatch- 
ing of  fly  eggs  in  these  areas  give  rise  to  infestation  with  destructive 
maggots,  causing  ulcers  and  other  complications  that  require  medical 
treatment.  These  statements  regarding  the  secondary  injurious 
effects  of  cattle  ticks  also  apply  to  those  ticks  which  have  l)een  pre- 
viously spoken  of  as  harmless  in  so  far  as  Texas  fever  is  concerned, 
and,  in  fact,  to  all  external  parasite's.  Therefore,  it  is  just  as  impor- 
tant to  eradicate  the  cattle  ticks  for  reasons  other  than  those  associ- 
ated with  Texas  fever  as  it  is  to  exterminate  lice,  fleas,  and  other 
vermin.  Furthermore,  cattle  ticks,  aside  from  the  losses  sustained 
by  their  purely  parasitic  effects,  are  the  greatest  menace  to  the  profit- 
able raising  and  feeding  of  cattle  in  the  South,  because  they  are  an 
obstacle  to  cattle  traffic  between  the  infected  and  noninfected  districts. 

LOSS    OCCASIONED    BY    CATTLK    TICKS. 

The  economic  aspect  of  the  tick  problem  is  unquestionably  of  the 
greatest  practical  interest,  since  the  fundamental  importance  of  all  the 
other  questions  which  surround  it  depends  upon  the  actual  money 
value  involved.  It  would  therefore  seem  advisable  to  furnish  a  few 
statistics  showing  the  financial  loss  sustained  by  the  country  as  a 
result  of  the  presence  of  this  parasite.  It  is  well  known  that  those 
animals,  coining  from  an  infected  district  and  sold  in  the  "southern 
pens''  of  northern  stockyards,  bring  an  average  of  one-fourth  to  one- 
half  a  cent  less  per  pound  than  the  quoted  market  price.  The  handi- 
cap that  is  placed  on  the  southern  cattle  raiser  as  a  result  of  this 
decrease  in  value  of  his  stock  will  average  at  tln>  former  figure  at 
least  $1.50  per  head,  allowing  an  individual  weight  of  (500  pounds  for 
nil  classes  of  animals,  so  that  the  loss  on  the  estimated  705,000 
southern  cattle,  including  stock,  beef,  and  dairy  animals,  marketed 
yearly  under  these  conditions  will  sum  up  a  loss  of  $1.0.") 7, 500  \w 
annum.  Carrying  this  estimate  still  further  it  will  be  found  that  this 
decreased  value  reacts  and  fixes  the  valuation  of  all  cattle  which 
remain  in  the  infected  territory,  thereby  reducing  the  assets  of  the 
cattle  industry  of  that  section  by  this  ratio  per  head  for  the  four  and 
a  half  millions  of  cattle  east  of  the  Mississippi  River  and  the  eleven 


20  .BUREAU  OF  ANIMAL  INDUSTRY. 

millions  of  cattle  west  of  the  Mississippi  River:  or.  altogether,  the 
enormous  shrinkage  in  value  of  $23,250,000  directly  chargeable  to  the 
cattle  tick.  This  sum.  however,  should  not  be  considered  in  determin- 
ing the  yearly  devastation  caused  by  the  cattle  tick,  but  rather  as  an 
unnecessary  reduction  in  the  assets  of  the  infected  country.  This  last 
loss  does  not  include  the  decrease  in  flesh  and  lack  of  development  of 
southern  cattle  <x-casioned  by  the  parasitic  life  of  the  ticks  from  with- 
out and  by  the  blood-destroying  and  enervating  properties  of  the 
protozoan  parasites  from  within,  an  additional  loss  which  is  so  very 
great  that  a  conservative  estimate  would  place  it  equal  to  the  loss 
above  mentioned,  or  $23,250,000. 

The  shrinkage  in  the  milk  production  of  cattle  harboring1  many 
ticks  will  average  1  quart  per  day.  and  the  loss  occasioned  thereby  at 
Jt  cents  per  quart  for  the  875.000  ticky  dairy  cattle  out  of  more  than 
•4.000,000  dairy  cattle  below  the  quarantine  line  would  amount  to 
$20.250  per  day,  or.  counting  three  hundred  milking  days  for  each 
cow  to  the  year,  $7,875.000  per  annum.  The  damage  resulting  to  the 
southern  purchaser  of  northern  purebred  or  high-grade  cattle  is 
another  item  of  no  small  moment.  About  10  per  cent  of  all  such  cattle 
taken  South  die  of  Texas  fever  even  after  they  are  immunized  by 
blood  inoculations,  and  about  00  per  cent  of  these  cattle  succumb  to 
Texas  fever  when  not  so  treated.  Since  they  are  usually  very  expen- 
sive animals  and  of  a  highly  valued  strain  of  blood,  the  loss  in  certain 
cases  is  excessive  and  in  others  almost  irreparable  owing  to  the  possi- 
ble extinction  of  some  particular  type  especially  selected  for  the 
improvement  of  the  herd.  Thus  of  the  approximate  4,(>00  of  such 
cattle  brought  South  each  year,  at  least  4(50  die  of  Texas  fever.  The 
loss  entailed  would  naturally  depend  on  the  value  of  each  animal,  and 
.since  the  prices  paid  for  such  well-bred  cattle  range  from  $100  to 
$1.000  or  even  more,  it  can  readily  be  conceived  that  the  yearly  loss 
from  this  item  alone  varies  from  $40,000  upward. 

Another  instance  where  it  is  difficult  to  figure  the  injury  done  by 
the  ticks  is  in  the  case  of  death  of  nonimmune  cattle  in  the  tick-free 
pastures  of  the  South.  Such  animals  are  as  susceptible  to  Texas 
fever  as  nonimmune  northern  cattle,  and.  inasmuch  as  there  are  in 
many  State-  only  one  out  of  every  four  farms  infested  with  ticks, 
the  cattle  on  the  remaining  farms  will  in  many  cases  contract  Texas 
fever  when  exposed  to  the  fever  tick.  These  losses  can  scarcely  !>:• 
computed,  as  the  death  rate  depends  so  much  on  the  season  of  tin- 
year  when  exposure  occurs  and  on  the  age  of  the  animal  affected. 
However,  the  deaths  among  such  cattle  are  considerable,  although 
this  fact  is  little  appreciated  or  understood  by  many  outside  of  the 
infected  area.  Thus,  if  we  consider  one-tenth  of  the  cattle  below 
the  line  as  nonimmunes  which  contract  the  disease  on  exposure  to 
ticks,  and  if  we  figure  on  the  death  rate  of  25  per  cent  of  these 


TEXAS    FEVER    AND    ITS    PREVENTION.  21 

animals — a  conservative  estimate — the  loss  would  amount  to  387.500 
animals,  which,  at  an  estimated  value  of  $15  per  head,  would  amount 
to  a  loss  of  $5,812,500  per  annum.  And  this  sum,  excessive  as  it 
may  seem,  represents  a  smaller  percentage  of  loss  on  the  total  valu- 
ation of  neat  cattle  than  has  been  determined  by  several  of  the 
infected  States. 

On  rare  occasions  a  small  outbreak  of  Texas  fever  occurs  north 
of  the  quarantine  line  as  a  result  of  improperly  disinfected  cars,  of 
unscrupulous  dealers  breaking  the  quarantine  regulations,  or  of 
some  accidental  condition.  Such  damage,  however,  is  slight,  but 
should  be  given  consideration  in  summing  up  the  loss  occasioned 
by  the  fever  tick. 

The  advertisement  which  a  breeder  obtains  and  the  sales  which  are 
made  by  having  his  stock  in  the  show  ring  are  usually  lost  to  the 
southern  cattle  raiser  who  aspires  to  display  his  animals  in  the 
North,  as  they  are  barred  from  most  of  these  exhibitions.  On  the 
other  hand,  the  southern  farmer  is  not  given  an  opportunity  to  sec 
and  be  stimulated  by  the  fine  specimens  of  northern  cattle  which 
might  be  shown  at  southern  stock  exhibits,  for  the  reason  that  the 
danger  of  contracting  Texas  fever  is  too  patent  to  warrant  such 
exposure.  The  expense  incurred  by  the  Government  in  enforcing 
the  regulations  that  apply  to  the  quarantine  line  reaches  about  $42,000 
per  annum,  while  the  cost  to  the  various  States  for  similar  work 
along  their  individual  quarantine  lines  amounts  to  a  very  modest 
sum  in  some  States,  but  to  large  figures  in  others,  aggregating  alxnit 
$23,000  yearly. 

Another  loss  which  is  indirectly  sustained  by  the  southern  cattle 
industry  through  increased  freight  rates  is  the  cost  to  the  railroad 
companies  of  cleaning  and  disinfecting  the  cars  that  carry  southern 
cattle  and  in  providing  separate  pens  for  these  animals  at  various 
locations.  This  sum  may  be  calculated  at  not  less  than  $2J).()00  per 
annum. 

If  all  the  above-mentioned  losses  are  added  it  will  be  found  that 
the  Texas-fever  tick  is  responsible  for  about  $40.000.000  of  loss  an- 
nually to  the  people  of  the  infected  country,  and  that  it  also  lowers 
the  assets  of  the  South  by  an  additional  $23,250.000.  These  figures 
are  not  given  as  accurate  in  any  particular,  but  they  are  sufficiently 
close  to  indicate  that  the  loss  to  the  quarantined  section  from  the 
cattle  tick  is  something  enormous  and  represents  about  1<>  per  cent  of 
the  total  valuation  of  the  cattle  in  that  region.  It  must  IH>  admitted 
that  this  is  by  far  too  great  a  barrier  to  the  successful  operation  of  any 
business.  Such  a  series  of  encumbrances  as  those  recorded  could  be 
carried  by  the  cattle  industry  of  no  other  section  of  the  country  but 
the  South,  whose  excellent  pastures,  rich  soil,  and  salubrious  climate 
are  the  only  reasons  for  its  ability  to  overcome  such  obstacles  in  meet- 


22  BUREAU   OF   ANIMAL   INDUSTRY. 

ing  the  competition  of  the  West.  And  it  is  the  inherent  capacity  of 
the  South  for  greatly  increasing  its  herds  and  enlarging  its  pasture 
lands  that  makes  the  actual  los*  even  secondary  to  the  potential  loss 
due  to  restrictions  necessitated  by  the  presence  of  the  cattle  tick. 
This  potential  loss  may  he  described  as  the  difference  between  the 
value  of  the  cattle  industry  of  the  South  to-day  and  the  extent  to 
which  this  industry  would  be  increased  if  farmers  and  ranchmen 
were  assured  that  their  lands  and  cattle  would  not  become  infested 
with  fever  ticks.  Could  this  assurance  be  given  the  beneficial  effects 
would  extend  over  the  entire  country,  because  the  market  of  the 
northern  breeder  would  thereby  become  greatly  extended. 

These  appalling  losses  and  annual  sacrifices  of  the  cattle  raisers  of 
the  infected  district  can  be  entirely  effaced,  and  this  at  a  small  pro- 
portionate cost:  for.  with  enthusiastic  stockmen,  satisfactory  State 
legislation,  sufficient  money,  and  a  trained  corps  of  inspectors,  the 
cattle  tick  may  be  exterminated,  and  every  dollar  expended  in  this 
work  will  be  returned  many  fold  during  each  succeeding  year. 

PERIOD  OF  DEVELOPMENT  OF  DISEASE  AFTER  EXPOSURE  TO  TICKS. 

The  length  of  time  elapsing  between  the  exposure  of  susceptible 
cattTe  to  the  cattle  tick  and  the  apjx'arance  of  Texas  fever  among 
them  is  dependent  upon  the  climate  and  the  development  of  the  ticks 
to  which  they  are  exposed.  Thus,  if  any  Northern  animals  are  placed 
\\\wu  pastures,  highways,  or  in  pens,  cars,  etc.,  in  summer  immedi- 
ately after  the  premises  have  been  infested  with  ticks  from  Southern 
cattle,  Texas  fever  may  occur  in  from  thirty  to  sixty  days,  as  the 
females  that  drop  from  the  Southern  cattle  must  lay  eggs  and  these 
must  hatch  before  the  Northern  animal  becomes  infested  with  ticks, 
and  thereby  inoculated  with  the  disease.  In  cool  weather  this  period 
may  extend  to  ninety  days,  as  it  takes  much  longer  for  the  eggs  to 
hatch.  Where  Northern  animals  are  not  exposed  in  an  infested  pas- 
ture until  the  ticks  which  fell  from  the  Southern  cattle  have  laid  eggs 
and  the  larva',  or  seed  ticks,  are  already  present,  the  former  cattle  will 
develop  symptoms  in  thirteen  to  fifteen  days  in  hot  weather.  Tims 
under  natural  conditions  the  disease  appears  in  thirteen  to  ninety 
days  after  exposure.  After  the  seed  ticks  lx»coine  attached  to  the 
animal  the  disease  will  appear  in  about  ten  days  in  summer,  and  after 
a  somewhat  longer  period  in  cooler  weather.  In  fact,  the  disease  may 
occur  before  the  ticks  are  large  enough  to  be  seen  without  a  very  care- 
ful search.  By  artificially  inoculating  a  cow  under  the  skin  or  into  a 
vein  with  virulent  blood  the  disease  may  IK-  produced  in  three  to  ten 
days. 

SYMPTOMS. 

The  symptoms  of  Texas  fever  present  two  distinct  types,  depending 
upon  the  time  of  year  the  disease  makes  its  apj>earance  and  the  sus- 


TEXAS  FEVER  AND  ITS  PREVENTION?  23 

ceptibility  of  the  animals  attacked.  These  types  are  spoken  of  as  the 
acute  and  chronic  forms  of  the  disease.  The  acute,  fatal  form  is 
seen  when  nonimmune  Northern  cattle  and  the  susceptible  Southern 
animals  raised  on  tick-free  pastures  are  attacked  in  the  hot  summer 
months.  The  milder,  chronic  form,  usually  nonfatal,  occurs  when 
nonimmune  cattle  are  affected  in  the  late  autumn  and  in  the  partially 
immune  cattle  below  the  Texas- fever  quarantine  line  at  all  seasons 
of  the  year,  the  latter  animals  usually  not  being  attacked  by  the  acute 
form  of  the  disease. 

Acute  type. — In  this  form  of  the  disease  the  temperature  rises 
within  twenty-four  to  forty-eight  hours  to  107°  or  108°  F.,  and  the 
animal  rapidly  shows  signs  of  being  affected  with  a  severe  malady. 
It  is  depressed,  leaves  the  herd,  and  lies  down  or  stands  off  by  itself 
with  head  lowered,  ears  dropped,  feet  drawn  together,  and  back 
arched  from  the  pain  in  the  liver  and  kidneys.  If  the  nature  of  the 
disease  is  suspected,  the  rise  of  temperature  may  be  ascertained  by 
the  use  of  the  thermometer  or  by  merely  placing  the  hand  about  the 
root  of  the  tail  or  between  the  thighs.  The  muzzle  is  dry,  the  appe- 
tite lost,  and  rumination  ceases.  Constipation  is  always  present 
during  the  first  stages  of  the  disease,  but  it  frequently  gives  place 
later  to  diarrhea,  and  the  manure  is  usually  heavily  stained  with  bile 
and  in  rare  cases  may  be  mixed  with  blood.  Accompanying  the  rise 
of  temperature,  as  in  all  other  acute  febrile  diseases,  there  is  an  in- 
crease in  the  rate  of  respiration  and  pulse  beat.  The  former  may 
rise  to  from  50  to  90,  while  the  latter  varies  from  90  to  1*20  per  minute. 

The  changes  which  occur  in  both  the  urine  and  blood  are  extremely 
important,  but  the  urine  will  receive  first  consideration  here,  as  it  is 
more  readly  examined  by  the  layman  than  the  blood.  The  pecul- 
iarity of  the  urinary  secretion  is  that  it  is  blood-stained — the  so- 
called  hemaglobinurea— from  which  symptom  the  disease  has  de- 
rived its  name  of  "  red  water."  The  protozoa  in  the  circulation 
break  up  the  red  corpuscles,  liberating  the  substance  hemaglobin. 
which  is  the  coloring  matter  of  the  blood.  This  substance  U'ing 
free  in  the  blood  plasma  is  excreted  by  the  kidneys,  giving  the  urine 
its  red  color,  which  is  so  characteristic  of  Texas  fever.  This  dis- 
coloration of  the  urine  is  present  in  the  majority  of  the  acute  cases, 
but  it  is  frequently  wanting  in  the  chronic  form  of  the  disease.  The 
color  varies  greatly  from  a  mere  pinkish  tint  to  an  almost  black 
color,  depending  on  the  rapidity  of  destruction  of  the  red  cells  and 
the  excretion  of  the  coloring  matter  through  the  kidneys  into  the 
urine.  There  is  also  a  small  quantity  of  albumen  in  the  urine  of 
the  majority  of  cases.  The  comparative  weight  (specific  gravity)  of 
the  urine,  which  in  the  beginning  stages  is  increased  (1,0*28  to  1.040), 
is  later  reduced  to  normal  (1,010  to  1.020). 

The  blood  also  furnishes  great  assistance  in  making  a  diagnosis 


24  BUREAU  OP  ANIMAL  INDUSTRY. 

of  suspected  Texas  fever,  and  the  finding  of  the  intraeorpuscular 
parasite  microscopically  is  conclusive  evidence.  This  fluid,  as  it 
oozes  from  a  small  incision  in  the  skin,  is  pale  and  watery,  indicative 
of  great  reduction  in  the  cellular  element,  and  is  readily  seen  to 
differ  markedly  from  the  normal  red  blood  of  healthy  animals. 
Sometimes  there  is  such  a  lack  of  blood  in  the  vessels  of  the  skin 
that  a  very  deep  incision  has  to  l>e  made  in  order  to  obtain  sufficient 
blood  for  inspection.  It  is  also  at  times  noted  that  the  power  of 
coagulability  of  the  blood  is  so  reduced  that  when  it  once  starts  to 
flow  it  is  only  after  a  considerable  time — or  by  applying  pressure — 
that  the  hemorrhage  is  stopped.  In  the  majority  of  cases,  however, 
the  tendency  of  the  blood  to  clot  is  unaffected. 

Cerebral  symptoms  are  noticed  in  a  certain  percentage  of  cases 
manifesting  themselves  in  the  form  of  staggering  gait,  disturbances 
of  vision,  or  delirium.  There  is  in  milch  cows  a  reduction  or  a  com- 
plete stopping  of  the  milk  secretion.  Abortion  is  also  very  common 
in  pregnant  animals.  Death  usually  occurs  within  three  or  four  days, 
and  is  generally  preceded  by  a  marked  fall  of  body  temperature  to 
normal  or  even  subnormal  a  few  hours  before  the  fatal  termination. 
In  nonfatal  cases  the  temperature  falls  gradually  after  the  crisis  and 
soon  reaches  the  normal,  but  recovery  is  prolonged  over  weeks  and 
even  months,  as  a  great  deal  of  time  is  required  to  regenerate  the 
greatly  impoverished  blood. 

Chronic  type. — This  form  of  the  disease  appears  under  natural 
conditions  usually  in  the  late  autumn  and  early  winter.  It  can  l>e 
produced  experimentally,  however,  by  placing  a  few  ticks  on  the  skin 
of  a  susceptible  animal — a  fact  of  very  great  importance  in  the  pro- 
duction of  immunity  against  the  acute  type  among  Northern  cattle. 

This  form  shows  all  the  symptoms  of  the  acute  type,  but  in  a  milder 
degree.  The  temperature  usually  remains  about  103°  and  never 
exceeds  105°  F.  There  is  loss  of  appetite,  stoppage  of  rumination, 
constipation,  and  albumen  in  the  urine.  An  anemic  condition  of  the 
blood,  as  indicated  by  the  pale  and  bloodless  mucous  membranes,  is 
also  present,  but  hemaglobin  is  not  usually  excreted  by  the  urine, 
hence  the  red-water  symptom  is  absent.  There  is  also  excessive  loss 
of  flesh  and.  IK* fore  the  end  of  the  attack,  the  affected  animal  is  greatly 
emaciated:  although  death  rarely  occurs  the  valuation  of  the  animal 
is  much  reduced. 

Iti'ltipxex. — Following  recovery  from  an  acute  attack,  when  the  red 
blood  corpuscles  have  apparently  reached  their  normal  number,  there 
has  frequently  Ix-en  observed  a  relapse  or  recurrence  of  the  disease  in 
the  mild,  chronic  form,  accompanying  which  there  is  a  second  period 
of  destruction  of  the  red  cells.  This  follows  within  three  to  six 
weeks  after  the  symptoms  of  the  acute  attack  have  subsided.  For  a 
considerable  time  it  was  unknown  whether  this  was  a  relapse  of  the 


TEXAS  FEVER  AND  ITS  PREVENTION.  25 

acute  attack  or  due  to  reinfection  from  a  second  generation  of  ticks. 
Smith  and  Kilborne,  however,  proved  that  it  could  occur  as  a  relapse 
without  the  presence  of  ticks,  but  it  may  also  in  some  cases  be  caused 
by  a  second  extraneous  infection. 

APPEARANCE    AFTER    DEATH. 

The  postmortem  examination  should  be  made  as  soon  as  possible 
after  death,  as  the  carcass  of  an  animal  dead  of  Texas  fever  under- 
goes decomposition  very  rapidly.  The  skin  should  always  l>e  first 
examined  for  the  presence  of  the  cattle  tick,  as  the  discovery  of  any 
of  the  forms  of  this  parasite  on  the  skin  of  the  escutcheon,  thigh,  or 
belly  leads  at  once  to  a  suspicion  of  the  presence  of  the  disease.  The 
skin  is  usually  normal  in  appearance,  no  visible  alterations  being 
present  except  possibly  the  small  swellings,  minute  hemorrhages,  and 
perforations  from  the  bites  of  the  ticks.  Upon  cutting  into  the  hide 
and  skinning  the  carcass,  a  marked  lack  of  blood  in  the  bl<x>d  vessels 
of  the  skin  and  underlying  tissues  is  observed.  Occasionally  there 
may  be  noted  a  yellowish,  jaundiced  discoloration  of  these  tissues. 
The  fatty  tissues  are  also  yellowish,  and.  instead  of  possessing  the  nor- 
mal firm  consistency,  they  are  soft  and  oily.  In  very  severe  cases, 
even  the  muscular  system  may  have  a  jaundiced  appearance.  This 
discoloration  is  due  to  the  alteration  of  the  bile-secreting  function  of 
the  liver,  but  is  by  no  means  present  in  all  cases,  being  most  constant 
in  the  acute,  rapidly  fatal  form  of  the  disease. 

Probably  the  most  marked  pathologic  alterations  in  the  disease 
are  found  in  the  liver.  This  organ  is  very  much  enlarged  and  has 
a  yellowish,  mahogany-brown  color,  due  to  the  bile  it  contains.  This 
secretion  becomes  excessive,  and  minute  plugs  of  congealed  bile  form 
in  the  small  bile  ducts,  thus  stopping  them  and  damming  the  bile 
in  the  organ,  which  produces  the  yellowish  color.  This  does  not 
occur  evenly  throughout  the  organ,  and  consequently  it  has  a  mottled 
appearance.  The  gall  bladder  is  usually  distended  with  bile,  and  its 
mucous  membrane  often  contains  numerous  minute  hemorrhages  or 
petechial  spots.  The  bile  is  very  thick,  has  the  appearance  of 
"chewed  grass,"  and  contains  numerous  firm,  irregular  flakes.  The 
spleen  also  shows  marked  pathologic  alterations.  Normally  this 
organ  weighs  from  H  to  *2\  pounds,  but  in  cases  of  Texas  fever  it  is 
enormously  enlarged,  sometimes  reaching  four  times  its  normal  dimen- 
sions. It  is  very  dark  at  times,  almost  black  in  color,  due  to  the 
enormous  accumulation  of  red  corpuscles  and  hemaglobin  within  its 
substance.  Upon  cutting  into  the  spleen,  or  merely  attempting  to 
pinch  it  up,  the  pulpy  tissue  will  sometimes  run  out  as  a  semifluid, 
blackish  mass,  due  to  the  In-eaking  down  of  its  structures  and  to  the 
excessive  engorgement  Of  the  organ. 


2(>  BUREAU    OF    ANIMAL    INDUSTRY. 

In  death  from  the  acute  type  of  the  disease  the  kidneys  are  usually 
found  to  be  very  dark  in  color  and  congested,  and,  on  cross  section, 
the  normal  markings  an'  indistinguishable.  The  blood  vessels  are 
engorged  with  blood,  and  there  is  edematous  infiltration  of  the  sur- 
rounding fatty  tissue.  In  the  older,  more  chronic  cases,  the  kidneys 
are  paler  and  somewhat  flabby. 

The  bladder  usually  .contains  a  varying  quantity  of  urine,  which 
may  or  may  not  l>e  blood-stained.  The  mucous  membrane  frequently 
contains  a  few  minute  hemorrhages. 

No  characteristic  lesions  are  found  in  the  stomach  and  intestines. 
There  may  be  slight  congestion  of  the  third  and  fourth  stomach,  with 
slight  peeling  off  of  the  epithelial  lining.  The  intestines  usually  con- 
tain considerable  bile  and  there  is  more  or  less  edema  of  their  walls. 
Blood  effusions  may  have  occurred  from  the  walls  of  the  gut,  espe- 
cially in  the  rectum,  producing  a  bloody  discoloration  of  the  feces. 
The  large  intestine  also  frequently  shows  severe  congestion.  None  of 
these  lesions,  however,  are  constant,  and  the  intestines  furnish  very 
little  positive  information  in  establishing  a  diagnosis.  The  lungs  are 
rarely  affected  by  the  disease  and.  barring  a  slight  edema,  are  found 
to  be  in  a  healthy  condition. 

The  membrane  surrounding  the  heart  (pericardium)  frequently 
^hows  pin-point  hemorrhages,  as  does  also  the  membrane  on  the  inner 
surface  (endocardium)  lining  the  walls  of  the  heart  cavities.  The 
blood  is  observed  to  lx>  paler  and  the  clots  softer  than  normal. 

COURSE    AND    TERM  I  NATION. 

The  course  of  the  disease  depends  not  only  upon  the  time  of  the 
year  the  infection  occurs,  but  also  on  the  age,  strength,  and  suscepti- 
bility of  the  animals  attacked.  When  mature  susceptible  cattle  con- 
tract the  disease  in  the  hot  summer  months,  death  usually  occurs 
within  a  week — generally  three  or  four  days — after  the  first  appear- 
ance of  symptoms,  but  it  may  follow  inside  of  twenty-four  hours. 

In  the  late  fall  infections  of  nonimmune  cattle  and  in  the  partially 
immune  Southern  cattle,  however,  the  course  of  the  disease  is  much 
more  prolonged  and  covers  a  ]x»riod  of  many  weeks  or  even  several 
months.  In  this  type  the  continuous  fever  causes  exhaustion,  while 
at  the  same  time  the  enormous  destruction  of  red  blood  cells  interferes 
very  materially  with  the  nutrition  of  the  patient.  As  a  natural  con- 
sequence, emaciation  Ix'comes  marked,  and  this,  together  with  the 
poor  appetite,  leads  to  a  fatal  result  in  some  cast's.  In  the  majority 
of  cases,  however,  in  spite  of  the  severe  alterations  of  the  blood  and 
internal  organs,  they  l>egin  after  several  weeks  to  show  improve- 
ment. The  teni|M>rature  l>eeomos  normal  and  there  is  a  tendency 
toward  regeneration.  This,  however,  requires  weeks  and  months,  the 


TEXAS   FEVER   AND    ITS    PREVENTION.  27 

animals  in  the  meantime  appearing  weak  and  thin,  having  pale 
mucous  membranes.  During  the  recuperative  period  the  animal 
should  by  no  means  be  fed  excessively,  as  numerous  cases  of  fatal 
gastro-intestinal  disturbances  have  been  reported  from  overfeeding. 
The  few  animals  which  recover  from  the  acute  type  of  summer  are 
quite  likely  to  have  a  relapse  in  the  form  of  the  chronic  type  in  the 
fall. 

The  mortality  in  adult  susceptible  cattle,  as  the  alcove  statements 
readily  show,  may  vary  considerably,  and  ranges  from  i)0  per  cent  in 
the  months  of  July  and  August  to  less  than  .">()  per  cent  in  the  late 
autumn  and  early  winter.  The  prognosis  must  therefore  depend 
on  the  time  of  year  the  outbreak  occurs.  In  animals  under  0  months 
of  age,  the  course  of  the  disease  is  usually  short  and  the  affection 
seldom  fatal,  while  the  death  rate  among  1-year-old  cattle  during  the 
hot  season  is  about  25  per  cent,  and  less  than  10  per  cent  in  the  fall 
and  winter.  Between  1£  and  2  years  of  age,  the  mortality  is  about 
double  that  at  1  year. 

INFECTIVE    CHARACTER. 

Texas  fever  belongs  to  the  group  of  infectious  diseases,  and  it  is  a 
typical  example  of  the  few  diseases  of  this  class  which  do  not  com- 
bine the  property  of  being  contagious.  It  is  infectious  because  it  is 
due  to  the  entrance  and  multiplication  of  a  pathogenic  microorganism 
within  the  body,  but  sick  animals,  in  the  absence  of  ticks,  can  remain 
in  intimate  association  with  healthy  susceptible -animals  indefinitely 
without  transmitting  to  them  the  disease,  and  hence  it  is  not  con- 
tagious. Furthermore,  a  cow  perfectly  healthy  in  appearance  may 
contain  in  its  blood  the  Texas  fever  protozoan,  which,  when  trans- 
mitted to  susceptible  cattle  by  the  fever  tick,  will  produce  the  disease. 
It  is  certain  that  the  piroplasma  are  present  in  varying  numl>ers  in 
the  manure  and  urine  of  infected  animals,  and  yet  susceptible  animals 
have  never  been  known  to  become  affected  from  grazing  over  tick-free 
pastures  soiled  with  excrement  from  the  sick  animals. 

In  1890  the  experiment  was  made  by  the  Bureau  of  polluting  a 
pasture  with  the  blood  and  spleen  of  an  animal  dead  of  Texas  fever 
and  then  allowing  susceptible  cattle  to  graze  in  the  field  for  two 
months,  but  the  animals  remained  perfectly  healthy.  Moreover,  as 
has  previously  been  stated,  the  feeding  of  ground-up  ticks  and  viru- 
lent blood  failed  to  produce  the  disease,  showing  that  the  digestive 
tract  is  proof  against  the  infection. 

The  disease  therefore  can  be  transmitted  by  three  known  method* 
only:  (1)  By  the  bite  of  the  cattle  tick:  (2)  by  inoculating  the 
blood  of  sick  animals  into  healthy  animals:  (X)  by  inoculating  the 
infected  blood  of  apparently  healthy  Southern  cattle  into  nonimmune 
cattle. 


28  BUREAU    OF    ANIMAL    INDUSTRY. 

ANIMALS    AFFECTED. 

Numerous  experiments  have  IHHMI  made  on  various  species  of  ani- 
mals with  highly  virulent  bhxul  from  cattle  suffering  with  Texas 
fever,  hut  the  disease  has  heen  produced  in  ho  vines  only.  Among 
those  animals  that  have  failed  to  develop  the  disease  after  inocula- 
tion may  l>e  mentioned  horses,  asses,  sheep,  pigs,  dogs,  cats,  mice, 
rats,  guinea  pigs,  rabbits,  chickens,  and  pigeons.  All  bovine  animals 
that  have  never  IKHMI  exposed  to  the  disease  are  susceptible  to  Texas 
fever,  although  sucking  calves  are  so  resistant  as  to  be  practically 
immune.  Adult  cattle  are  the  most  susceptible,  and.  if  attacked  in 
the  summer  months,  usually  die,  while  in  the  fall  and  winter  they 
more  frequently  recover.  Calves  under  8  months  of  age  contract  the 
affection  in  a  very  mild  form,  as  a  result  of  which  they  become  im- 
mune from  the  disease. 

DISEASES    MISTAKEN    FOR    TEXAS    FEVER. 

There  are  two  diseases  of  cattle  which  may  lx>  confounded  with 
Texas  fever.  The  differential  diagnosis  of  the  latter  and  anthrax  is 
by  far  the  more  important,  and  it  will  therefore  receive  first  consider- 
ation. Although  these  two  diseases  are  frequently  mistaken  one  for 
the  other,  there  are  numerous  differences  l>etween  them  which,  if  care- 
fully considered  and  taken  together,  are  usually  sufficient  to  establish 
a  diagnosis.  The  following  are  the  main  features  of  Texas  fever  not 
found  in  anthrax:  Young  ticks  are  usually  found  on  the  hide  of  the 
affected  animal:  if  occurring  in  the  uninfected  territory,  the  disease 
can  invariably  IK>  traced  to  the  shipment  of  Southern  cattle  into  the 
country  thirteen  to  ninety  days  previously:  young  sucking  calves  are 
not  affected:  the  mucous  membranes  become  extremely  pale  and 
jaundiced,  while  in  anthrax  they  are  very  red  and  congested;  cattle 
only  are  attacked,  while  anthrax  attacks  all  animals.  Upon  postmor- 
tem examination  in  Texas  fever  the  tissues  under  the  skin  are  very 
pale,  while  in  anthrax  they  are  congested,  with  the  blood  vessels  stand- 
ing out  prominently.  The  blood  is  thin,  pale,  and  watery,  whereas  in 
anthrax  it  is  tarry,  black,  and  incoagulable.  The  bile  is  semisolid 
and  contains  numerous  hard  flakes,  while  in  anthrax  it  is  fluid.  The 
>pleen  is  affected  quite,  similarly  in  Ixith  diseases,  but  the  liver  in 
Texas  fever  is  enlarged,  yellowish,  and  mottled  from  the  plugging 
of  the  bile  ducts,  whereas  in  anthrax  the  liver,  although  enlarged,  is 
very  dark  in  color  and  is  congested. 

It  can  usually  IK-  differentiated  from  blackleg  by  the  fact  that  the 
great  majority  of  victims  of  blackleg  are  l>ctween  (»  months  and  '2 
years  of  age.  There  is  usually  a  total  absence  of  ticks  on  the  hide  in 
the  latter  disease,  while  there  are  present  superficial  crackling  swell- 


TEXAS    FEVER    AND    ITS    PREVENTION.  29 

ings  which  on  being  opened  are  found  to  contain  gas  hubbies  with 
the  peculiar  odor  characteristic  of  the  disease.  There  is  also  an  ab- 
sence of  blood-stained  urine.  On  postmortem  examination  in  black- 
leg the  muscular  tissues  beneath  the  swollen  areas  are  very  dark  and 
soft,  with  bloody  fluid,  while  the  liver,  spleen,  and  kidneys  are  appar- 
ently unaffected. 

TREATMENT. 

Medical  treatment  of  the  sick  has  generally  been  unsatisfactory, 
although  in  chronic  cases  and  those  occurring  late  in  the  fall  lx?ne- 
ficial  results  have  followed.  If  the  animal  is  constipated,  a  drench 
containing  1  pound  of  Epsom  salts  dissolved  in  1  quart  of  water 
should  be  administered,  followed  by  the  sulphate  of  quinine  in  doses 
of  30  to  90  grains,  according  to  the  size  of  the  animal,  four  times  a 
day  until  the  system  is  well  saturated  with  it.  Tincture  of  digitalis  £ 
ounce,  and  whisky  or  alcohol  2  ounces,  may  l>e  combined  with  the 
quinine,  according  to  indications  of  individual  cases.  An  iron  tonic 
containing  reduced  iron  2  ounces,  powdered  gentian  4  ounces,  pow- 
dered mix  vomica  2  ounces,  powdered  rhubarb  2  ounces,  and  potas- 
sium nitrate  (>  ounces  will  be  found  IxMieficial  in  the  convalescent 
stage  when  the  fever  has  run  its  course.  This  tonic  should  be  given 
in  heaping  tablespoonful  doses  three  times  a  day  in  the  food.  Good 
nursing  is  essential  in  treating  these  cases.  The  animal  should  l>e 
given  a  nutritious  laxative  diet,  with  plenty  of  clean  and  cool  drink- 
ing water  and  allowed  to  rest  in  a  quiet  place. 

If  the  stable  or  pasture  is  infested  with  ticks,  the  animal  should 
be  placed  in  a  tick-free  inclosure.  to  prevent  additional  infestation 
with  these  parasites  and  the  introduction  of  fresh  infection  into  the 
blood.  It  is  advisable,  not  only  before  but  also  during  treatment,  to 
remove  from  the  sick  cattle  all  ticks  that  can  be  seen,  as  they  keep 
weakening  the  animal  by  withdrawing  a  considerable  quantity  of 
blood,  and  thereby  retard  recovery. 

PREVENTION. 

It  is  generally  accepted  that  if  Southern  cattle  are  entirely  free 
from  that  species  of  tick  known  as  Hoo^h'tlux  ntniiiliitiix,  they  can 
be  allowed  to  mingle  with  the  most  susceptible  animals  without  dan- 
ger. Furthermore,  it  has  been  learned  from  the  study  of  the  life  his- 
tory of  the  cattle  tick  and  from  the  fact  that  this  tick  infests  pastures 
only  transiently,  never  permanently,  and  will  not  mature  except 
upon  cattle  or  equines,  that  its  extermination  is  possible,  and  that 
the  disease  it  causes  may  be  prevented.  The  various  methods  with 
these  results  in  view  should  be  directed  toward  the  destruction  of 
ticks  on  cattle  as  well  as  their  eradication  from  the  pastures. 


30  BUREAU    OF    ANIMAL    INDUSTRY. 

HOW    TO   FREE  CATTLE  OK  TICKS. 

Among  the  most  important  measures  to  be  adopted  in  eradicating 
these  parasites  from  cattle  in  the  infested  districts  may  lx>  mentioned: 
(1)  Picking  or  brushing  them  off:  (*J)  smearing  or  spraying  the 
animals  with  a  disinfecting  solution,  and  (3)  dipping  the  "  ticky  r' 
animals  in  a  vat  containing  a  solution  capable  of  killing  the  ticks 
without  injury  to  the  cattle. 

The  systematic  application  of  one  or  more  of  these  methods,  to- 
gether with  appropriate  measures  for  eradicating  or  destroying  the 
cattle  ticks  upon  pastures,  has  been  successfully  adopted  in  certain 
sections,  and  has  thus  diminished  the  area  of  the  infested  district. 

Pickiny  or  bntxhhiy  tick  a  off  cuttle. — Where  the  herd  is  small  a 
very  effective  but  laborious  method  is  to  pick  off  these  parasites  by 
hand  or  to  scrape  them  off  with  a  dull  knife  or  a  currycomb.  This 
should  l>e  done  at  least  three  times  a  week  in  order  to  find  all  the 
adults  before  they  mature  and  fall  off,  as  by  this  system  the  smaller 
ticks  which  at  first  escaped  detection  will  be -found  before  they  are 
fully  developed.  After  removing  the  ticks  they  should  be  destroyed, 
preferably  by  burning.  Care  should  be  taken  to  go  over  all  parts 
of  the  animal  frequented  by  the  ticks,  especially  under  the  belly, 
it  round  the  tail  and  udder,  and  inside  the  legs.  After  the  ticks  are 
picked  or  brushed  off.  the  cattle  should  not  be  neglected,  but  should 
be  carefully  examined  later  for  the  presence  of  ticks  which  have  been 
picked  up  in  the  meantime.  If  this  work  is  thoroughly  performed 
and  no  ticks  are  allowed  to  fall  off  and  lay  eggs  from  June  1  to  the 
end  of  November,  the  cattle  will 'be  free  of  ticks,  and  the  pastures 
will  have  had  an  opportunity  of  becoming  cleaned. 

Smearing  or  spraying  cattle  with  a  disinfecting  solution. — Greasing 
the  legs  and  sides  of  cattle  with  cotton-seed  oil,  fish  oil,  or  lieaumont 
crude  petroleum  will  assist  in  preventing  the  ticks  from  crawling  up 
on  the  body.  In  small  herds,  smearing  the  cattle  with  a  mixture  of  1 
gallon  of  kerosene,  1  gallon  of  cotton-seed  oil,  and  1  pound  of  sulphur, 
(>]•  with  a  mixture  composed  of  equal  parts  of  cotton-seed  oil  and 
crude  petroleum,  or  with  Beaumont  crude  oil  alone,  has  proxed  efli- 
cacious  when  applied  to  the  skin  two  or  three  times  weekly  during 
the  tick  season.  For  this  purpose  sponges,  syringes,  brushes,  mops, 
or  brooms  may  lx¥  used.  This  method  not  only  kills  the  older  ticks 
on  the  cattle  by  mechanically  plugging  up  their  breathing  pores  but 
also  makes  the  legs  so  slippery  that  the  seed  ticks  are  unable  to  get  a 
foothold  in  order  to  crawl  up  on  the  cattle.  Where  a  large  number 
of  animals  are  to  l>e  treated,  but  not  sufficient  to  make  it  advisable  to 
construct  a  dipping  vat,  spraying  the  infested  animals  has  given  very 
favorable  results.  The  animals  should  be  placed  in  a  chute  or  a  stall, 
or  tied  to  a  tree,  and  then  sprayed  with  Beaumont  oil  or  a  .">  per  cent 
solution  of  any  of  the  standard  coal-tar  dips.  The  solution  may  1x3 


TEXAS    FEVER    AND    ITS    PREVENTION.  31 

applied  by  means  of  a  force  pump,  such  as  is  used  by  orchardists  to 
spray  fruit  trees,  or  by  placing  the  solution  in  a  barrel  upon  a  wagon 
or  on  a  platform  above  the  animals  and  allowing  the  fluid  to  gravi- 
tate through  a  hose,  to  the  end  of  which  is  attached  an  ordinary 
sprinkling  nozzle.  The  solution  is  then  allowed  to  flow  over  the  skin 
of  the  animal,  especially  upon  the  legs  and  under  portions  of  the 
body.  If  the  cattle  are  on  tick-infested  pastures,  this  treatment— 
either  smearing  or  spraying — must  be  continued  through  the  whole 
season,  and  if  thoroughly  done  it  will  leave  the  fields  free  from  ticks 
the  following  year. 

Dlpp'mg  in  a  fat. — Many  efforts  have  been  made  to  discover  a 
practical  method  for  dipping  cattle  to  destroy  ticks  without  injury  to 
the  cattle,  and  the  Bureau  has  experimented  for  years  with  this  object 
in  view.  Numerous  kinds  of  dips  have  been  used  and  many  failures 
have  been  recorded,  but  apparently  a  successful  one  has  been  found  in 
the  crude  oil — so-called  Beaumont  oil — obtained  from  certain  Texas 
wells.  This  oil  has  now  been  used  on  a  rather  large  scale,  and  it  has 
been  very  successful  in  killing  ticks  without  at  the  same  time  mate- 
rially affecting  the  health  of  the  cattle  when  the  proper  precautions 
have  been  observed.  In  fact,  it  is  distinctly  superior  to  any  of  the  other 
dips  that  have  been  tested.  In  these  experiments  it  was  found  that  a 
light  oil  heavily  charged  with  sulphur  is  the  most  desirable  for 
dipping  cattle,  as  the  heavy  oils  injure  the  animals  dipped  in  them. 
An  oil  with  40  per  cent  of  its  bulk  capable  of  boiling  between  -200° 
and  300°  C.,  having  a  specific  gravity  between  ±2i°  and  244°  Beaume, 
and  containing  1)  to  li  per  cent  of  sulphur  is  most  desirable,  and 
these  requirements  should  be  stipulated  before  purchase.  In  a  recent 
dipping  of  57,000  head  of  cattle  on  the  Kansas  and  Osage  Indian 
reservations  the  results  were  very  highly  satisfactory,  both  as  regards 
the  eradication  of  the  cattle  tick  and  the  after  results  of  the  dipping, 
since  the  loss  from  all  causes  was  less  than  0.7.">  per  cent.  This  loss 
represented  in  dollars  and  cents  would  amount  to  a  very  small  portion 
(about  one-twelfth)  of  the  loss  incurred  by  the  sale  of  these  animals 
as  "  ticky  "  cattle  in  the  stock  yards  of  the  North.  Other  cattle 
dipped  in  the  same  oil.  but  under  conditions  that  can  not  be  con- 
sidered parallel,  suffered  more  severely.  In  order  to  obtain  the  best 
results,  the  animals,  after  dipping,  should  not  be  unduly  exposed  to 
the  hot  sun  nor  driven  any  considerable  distance,  but  should  receive 
plenty  of  food  and  good  water.  They  should  be  allowed  to  stand 
for  four  or  more  days  after  dipping  and  prior  to  shipment.  Dip- 
ping should  not  be  attempted  until  after  they  shall  have  shed  their 
winter  coats,  as  a  large  percentage  of  all  cattle  dipped  before  the 
heavy  coat  is  lost  suffer  from  a  severe  irritation  of  the  skin.  The 
method  usually  adopted  in  dipping  cattle  is  to  construct  a  narrow 
swimming  tank  with  a  chute  at  one  end  for  the  entrance  of  the 


32  BUREAU  OF  ANIMAL  INDUSTRY. 

cattle  and  a  sloping  exit  at  the  other  end  where  the  cattle  emerge 
after  getting  a  uniform  coating  of  oil  in  passing  through  the  vat.  A 
drip  chute,  or  floor,  is  connected  with  the  exit  where  the  excess  of  oil 
is  allowed  to  drip  off  the  animals  and  to  drain  into  the  vat.  Plans 
and  specifications  for  installing  a  dipping  plant  suitable  for  either 
small  farms  or  large  ranges  are  published  in  Farmers'  Bulletin  No. 
152,  which  may  be  obtained  from  this  Department.  It  is  relatively 
more  exjxMisive  to  dip  cattle  in  tin*  South,  where  the  farms  and  plan- 
tations contain  a  small  numl>er  of  cattle,  than  in  the  range  country  of 
the  Southwest,  where  this  method  of  eradicating  ticks  becomes  not 
only  plausible  and  practicable,  but  also  economical.  When  cattle 
have  been  properly  dipped  in  Beaumont  crude  petroleum  or  any  other 
approved  petroleum  under  the  supervision  of  a  veterinary  inspector 
and  by  him  found  free  of  infection,  they  may  lx>  shipped  to  any  point 
above  the  quarantine  line,  subject  only  to  such  restrictions  as  may  l>e 
imposed  at  the  point  of  destination.  Such  cattle  must  be  shipped  in 
clean,  disinfected  cars,  and  must  not  be  driven  through  the  quarantined 
area  or  l>e  unloaded  therein,  except  at  those  points  designated  by  the 
Secretary  of  Agriculture.  It  is  earnestly  recommended  that  such 
shipments  shall  not  occur  earlier  than  four  to  eight  days  after  the 
dipping  is  performed. 

By  the  "soiling*  method. — This  method  of  freeing  cattle  of  ticks 
was  suggested  by  Curtice.  It  is  based  upon  a  knowledge  of  the  life 
history  of  these  parasites.  The  time  required  for  the  female  tick  to 
lay  eggs  and  the  latter  to  hatch — in  other  words,  the  time  spent  on 
the  ground — is  rarely  less  than  three  weeks,  and  the  period  required 
by  the  seed  ticks  to  molt  and  mature — or  the  time  spent  on  the  cattle- 
is  usually  from  twenty  to  forty-five  days.  When  cattle  infested  with 
ticks  are  to  be  cleaned  for  any  reason — as,  for  instance,  before  being 
placed  on  noninfested  pastures — it  is  recommended  that  the  cattle 
be  kept  in  a  small  tick-free  inclosure  for  three  weeks,  when  many 
of  the  ticks  will  have  fallen  off.  They  should  then  be  removed  and 
placed  in  a  similar  paddock  for  another  three  weeks.  At  this  lime 
the  cattle  should  l>e  examined,  and  if  found  free  from  ticks  they  may 
be  placed  in  the  noninfested  pasture  at  once.  On  the  other  hand  if 
any  ticks  are  observed  the  cattle  should  be  placed  in  a  third  pen  for 
two  weeks  more.  By  this  time  even  the  youngest  ticks  that  were  on 
the  cattle  at  the  start  will  have  matured  and  dropped  off:  and  as 
the  animals  are  removed  from  each  pen  In1  fore  they  could  possibly 
become  reinfested  with  the  seed  ticks  that  hatch  from  the  eggs  of 
the  females  that  fell  off.  they  are  now  tick  free.  The  same  pens  can 
not  be  used  repeatedly  for  this  purpose  without  thorough  disinfection, 
as  they  Ijecome  infested  with  young  ticks,  which  will  at  once  attack 
cattle  if  given  an  opportunity  to  do  so.  "are  should  be  taken  that 
hay  fed  the  animals  in  these  pens  is  from  noninfested  fields. 


TEXAS  FEVER  AND  ITS  PREVENTION.  33 


HO\V    TO    FREE    PASTURES    OK    TICKS. 


How  to  rid  pastures  of  ticks  without  destroying  the  vegetation  on 
them  was  for  a  long  time  a  problem.  While  this  may  be  impossible 
on  large  ranches,  it  has  been  successfully  accomplished  on  small 
farms  by  systematic  efforts  based  upon  a  knowledge  of  the  life  his- 
tory and  the  habits  of  the  cattle  ticks.  The  most  satisfactory  as  well 
as  the  most  practicable  methods  have  IXHMI  found  to  IKJ  as  follows: 
i  By  excluding  cattle  for  <t  definite  fx'nod. — The  removal  of  animals 
from  an  infested  pasture  for  a  stated  period  will  cause  all  ticks 
present  therein  to  starve  and  the  pasture  will  thus  l>ecome  tick-free. 
One  method  of  accomplishing  this  result  is  to  divide  the  pasture  into 
two  parts  by  a  double  line  of  fence.  This  fence  should  lx>  Ixiard- 
tight  at  the  bottom  to  prevent  ticks  from  crawling  out,  and  there 
should  be  a  10-foot  space  between  the  two  lines  so  that  the  ticks 
would  be  unable  to  crawl  across  to  the  opposite  pasture  if  they  should 
perchance  get  out.  One  of  these  pastures  is  then  kept  free  from 
cattle,  horses,  mules,  and  asses  from  spring  to  late  fall,  or,  better, 
until  January.  By  this  time  it  will  be  free  of  ticks  and  ready  for 
tick-free  cattle  that  have  been  cleaned  by  any  of  the  methods  al>ove 
described;  then  the  other  pasture  is  abandoned  for  the  same  period 
of  time. 

Butler  states  that  the  pasture  may  be  kept  free  of  ticky  animals  for 
a  shorter  period  with  equally  beneficial  results,  and  recommends  the 
following  method : 

The  tick-infested  cattle  should  be  removed  from  their  pasture  on 
September  1,  cleaned  of  ticks  by  any  of  the  methods  previously  men- 
tioned, and  placed  in  a  cultivated  field  or  pasture  where  no  ticky  ani- 
mals have  been  for  at  least  six  months  and  where  they  can  not  come 
in  contact  with  ticky  animals  or  ticky  soil.  The  original  pasture 
should  not  be  restocked  until  the  following  spring  (April),  at  which 
time  all  the  eggs  laid  there  lx»fore  September  1  will  have  hatched, 
the  seed  ticks  will  have  starved,  and  the  pasture  will  be  free  of  ticks. 
It  may  then  be  used  for  cattle  that  have  no  ticks  upon  them.  In 
case  the  cattle  are  not  free  of  ticks  when  placed  in  the  cultivated  field 
or  noninfested  pasture  on  September  1.  they  will  infect  this  field  and 
will  carry  ticks  to  the  original  pasture  if  placed  there  in  the  spring. 

/?//  ciiltirut'toH. — Another  method  of  destroying  ticks  on  pastures 
is  to  cultivate  the  soil  for  a  year  without  permitting  any  ticky  cattle, 
horses,  or  mules  on  the  ground  during  this  period.  After  this  treat- 
ment the  field  will  be  without  any  Texas-fever  ticks  and  may  be  re- 
stocked with  cattle  not  infested  with  these  parasites. 

By  burning  off  the  yraxx. — Pastures  that  are  too  large  to  lx?  dis- 
infected by  the  above  measures  or  those  grazing  lands  that  are  open 


34 


BUREAU    OF    ANIMAL    INDUSTRY. 


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TEXAS    FEVER    AND    ITS    PREVENTION.  35 

and  can  not  be  inclosed,  or  randies  where  a  division  of  the  pasture  is 
impracticable,  may  be  freed  from  ticks  by  burning  them  off  in  the 
spring  or  fall  and  then  keeping  tick-infested  animals  from  the  land. 
It  is  advisable  to  burn  off  the  grass  in  the  spring  when  practicable, 
as  this  permits  the  pasture  to  recover  quickly  and  to  supply  feed  in 
several  weeks. 

HOW    TO    FREE    CATTLE    AM)    I'ASTfKKS    OK    TICKS    AT    THE    SAME    TIME. 

By  the  ^'feed-lot"  nmthod. — -The  "  feed -lot  "  method  has  l>een  re- 
cently recommended  by  Morgan  after  conducting  field  e.\|M'riments 
in  Louisiana,  and  has  for  its  object  the  ridding  at  the  same  time  of 
pastures  and  cattle  of  the  fever  tick.  This  plan,  like  the  "soiling" 
method,  suggested  by  Curtice,  is  based  upon  the  length  of  time  the 
tick  lives  upon  cattle  and  the  period  required  for  the  eggs  to  l>e  laid 
and  hatched  and  the  seed  ticks  to  attach  themselves  to  their  host. 
For  carrying  out  this  idea  take  a  field  which  has  lw»en  sown  to  corn, 
millet,  sorghum,  or  other  forage  and  fence  off  three  lots  within  such 
a  field,  in  one  of  which  the  ticky  cattle  are  placed  on  June  1  by 
removal  from  their  customary  pasture."  (See  fig.  2.)  In  the  first 
feed  lot  the  greater  number  of  ticks  drop  off  and  lay  eggs.  After  an 
interval  of  twenty  days  and  before  these  eggs  have  had  time  to 
hatch,  the  cattle  are  moved  to  the  second  inclosure.  where  they  are 
kept  another  twenty  days,  when  they  will  in  many  instances  l>e  free 
of  ticks  and  can  be  turned  into  the  forage  field.  However,  in  case 
ticks  are  still  present,  the  cattle  should  be  placed  in  a  third  paddock 
for  fifteen  days  longer.  All  the  ticks  that  were  on  the  animals  when 
placed  in  the  feed  lots  will  have  dropped  off  now.  and.  as  the  cattle 
leave  each  feed  lot  before  they  can  become  reinfested  by  the  seed  ticks 
which  hatch  from  the  eggs  of  the  ticks  that  fall  off,  they  will  l>e  clean 
and  safe.  These  tick-free  cattle  are  then  pastured  in  the  sorghum, 
corn,  or  millet  field  containing  the  feed  lots  and  the  latter  are  plowed 
immediately  after  the  cattle  are  taken  out.  their  edges  are  sprayed 
with  Beaumont  oil.  petroleum,  or  other  disinfectant  substances,  and 
the  soil  is  cultivated.  The  cattle  are  kept  in  the  forage  field  until 
November  15,  or  even  later,  when  ;ill  the  ticks  on  the  regular  pasture 
will  have  died  of  starvation  from  the  exclusion  of  cattle  since  June  1.. 
and  the  tick-free  animals  can  then  l>e  replaced  on  this  tick-free  pas- 
ture. In  adopting  this  method  it  is  essential  that  the  feed  lots  lx- 
inclosed  by  a  fence  which  is  board-tight  along  the  ground,  and  that 
this  fence  be  watched  carefully  and  disinfected  occasionally  to  pre- 
vent the  ticks  from  getting  into  the  forage  field:  a  single  furrow 
could  be  thrown  up  on  both  sides  of  the  fence  for  the  same  purpose. 

«  From  our  experience  the  two  lots  recommended  by   Morgan   would  not   l>e 
sufficient  under  all  conditions. 


#0*  BUREAU  OF  ANIMAL  INDUSTRY. 

These  feed  lots  should  lx>  situated  along  the  edge  of  the  field  in  order 
that  the  cattle  in  changing  from  one  lot  to  the  other  may  pass,  as 
directly  as  possible,  through  a  portion  of  an  adjoining  cultivated  or 
tick-free  field,  so  that  if  the  ticks  fall  off  during  this  drive  they  will 
not  infest  the  forage  field,  and  later  the  cattle  when  pastured 
therein.  The  cattle  should  lx>  fed  on  the  annual  crops  while  in  these 
lots,  but  never  upon  crops  obtained  from  infested  pastures,  as  such 
food  may  contain  seed  ticks.  Water  may  l>e  supplied  by  piping 
from  a  well,  spring,  or  creek,  by  carting  it  to  the  feed  lots  in  barrels, 
or  by  placing  the  fence  so  as  to  include  a  spring  or  portion  of  a 
creek,  provided  the  latter  does  not  flow  through  an  infected  pasture 
a  short  distance  above. 

////  jMMfui'e  rotation. — A  very  satisfactory  method  for  freeing  cattle 
as  well  as  pastures  of  the  cattle  tick  is  by  pasture  rotation,  which  com- 
bines the  suggestions  of  Curtice,  Butler,  and  Morgan.  It  is  based 
upon  the  knowledge  that  by  severing  the  relation  of  the  fever  ticks 
and  the  animals  upon  which  they  develop  these  ticks  will  perish.  To 
adopt  this  plan  first  divide  the  infected  pasture  into  two  parts,  which 
is  best  accomplished  by  a  double  line  of  fence  with  a  10-foot  space  be 
tween  the  lines  to  prevent  ticks  crossing  from  one  pasture  to  another 
(fig.  3).  In  order  to  observe  all  possible  precautions,  this  fence 
should  have  either  a  furrow  thrown  up  against  it  or  a  board  or 
rail  placed  tightly  along  the  bottom  to  help  keep  the  ticks  within. 
All  animals  that  carry  the  cattle  tick  are  excluded  from  the  first  half 
of  the  pasture,  which  may  be  termed  pasture  No.  1,  from  June  1 
until  November  10,  at  which  time  all  the  ticks  that  were  there  will 
have  perished  from  want  of  a  host  and  the  field  will  be  ready  for  re- 
ceiving tick-free  cattle.  The  ticky  cattle,  on  l>eing  removed  from 
pasture  No.  1  on  June  1,  are  placed  in  the  other  half  of  the  original 
pasture,  which  may  be  called  pasture  No.  2.  where  they  are  kept  from 
June  1  to  September  10.  They  may  now  IK'  partly  cleaned  of  ticks 
by  placing  them  at  the  latter  date  (Septemlx»r  10)  in  a  cultivated 
field — for  instance,  a  rye  or  vetch  or  wheat  and  vetch  field — and  by 
keeping  them  therein  for  twenty  days,  when  a  large  numl>er  of  ticks 
will  have  fallen  off.  The  partly  cleaned  cattle  may  then  be  removed 
on  September  30  to  a  field  sown  to  corn  and  sorghum,  corn  and  cow- 
peas,  or  a  combination  of  corn,  sorghum,  and  cow  peas,  or-  other 
forage  crops. 

In  this  field  most  of  the  remaining  ticks,  if  not  all  of  them,  will 
have  dropped  from  the  animals  within  twenty  days,  but  in  a  few  in- 
stances the  cattle  may  still  l>e  infested,  so  the  animals  should  l>e  moved 
on  October  '20  to  a  cotton  field  in  which  rajx1  or  crimson  clover  had 
U>en  sown  at  the  last  cultivation  for  the  purpose  of  furnishing  food 
for  the  cattle  while  there.  The  crops  should  have  IXHMI  gathered  from 


TEXAS  FEVER  AND  ITS  PREVENTION. 


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38  Bl'KKAU    OF    ANIMAL    INDUSTRY. 

all  these  Holds  lief  ore  turning  in  the  cattle.  Here  they  are  kept  for 
another  twenty  days  (to  November  10),  not  liecause  they  would  not 
lie  free  of  ticks  at  an  earlier  date,  but  on  account  of  the  desire  to 
keep  cattle  away  from  pasture  No.  1  until  Novemlier  10.  On  this 
date  these  clean  cattle  are  returned  to  pasture  No.  1.  which 
will  now  be  tick-free  as  a  result  of  the  exclusion  of  animals 
since  June  1.  These-  cattle  should  be  kept  in  this  pasture  until 
May,  by  which  time  the  ticks  in  pasture  No.  "2  will  have 
starved,  owing  to  the  absence  of  animals  therefrom  since  Sep- 
temlier  10.  Both  the  cattle  and  pastures  will  now  IM»  tick-free  and 
the  double  line  of  fence  Ix'tween  the  two  fields  can  IK-  removed 
and  the  original  pasture  restored.  This  plan,  as  represented  by  the 
diagram,  is  merely  a  suggestion  of  arrangement  and  may  easily  be 
varied  with  regard  to  the  selection  of  crops  and  the  location  of  pas- 
tures to  suit  the  demands  of  individual  farms.  To  prevent  ticks 
from  crawling  under  either  of  the  fences  l>etween  fields  ITT  and  IV 
and  fields  IV  and  V,  it  is  necessary  to  have  a  board  or  rail  placed 
tightly  on  the  ground  along  these  lines  of  fence,  or  to  throw  up 
a  single  furrow  along  both  sides  of  the  fences.  To  avoid  the  danger 
of  infestation  from  the  outside,  care  should  lie  taken  to  feed  the 
animals,  in  those  cases  where  the  pastures  or  fields  are  overstocked, 
on  hay  cut  from  tick-free  fields,  and  to  keep  out  work  oxen,  mules, 
and  horses  that  may  harbor  fever  ticks,  thus  preventing  reinfesta- 
tion  of  the  pasture.  When  the  cultivated  fields  are  on  a  slope  it 
is  advisable  to  use  the  lowest  field  first,  in  order  that  the  ticks 
dropped  within  may  not  be  washed  by  drainage  upon  the  adjoin- 
ing fields  which  are  later  to  hold  the  cattle.  For  the  same  reason, 
where  a  stream  runs  through  the  fields  upon  which  the  cattle  are  to 
be  placed,  the  field  farthest  removed  from  the  head  water  should 
be  used  first.  Where  an  endeavor  is  made  to  rid  a  farm  of  ticks. 
it  is  essential  that  the  work  animals  (oxen,  mules,  and  horses)  used 
in  cultivating  the  fields  be  curried  to  keep  off  the  ticks  and  prevent 
the  latter  from  Ix'ing  carried  into  these  fields.  Cats  should  also  be 
kept  from  the  pastures  and  fields:  for.  although  they  do  not  harbor 
the  mature  ticks,  seed  ticks  have  been  found  on  them.  and.  while 
these  seed  ticks  remain  only  for  a  short  period,  this  time  may  IM« 
sufficient  to  allow  them  to  lie  carried  into  the  disinfected  pastures, 
where  they  may  fall  off  and  reinfest  the  soil.  If  a  farm  or  planta- 
tion consists  of  a  pasture  and  but  one  field  under  cultivation,  the 
alxive  plan  can  be  made  applicable  by  fencing  off  three  inclosures  in 
the  latter  and  by  rotating  the  cattle  in  them  every  twenty  days  in 
the  manner  just  described.  The  same  precautions  should  lie  observed 
in  changing  the  cattle  from  one  lot  to  another  and  in  preventing  ticks 
from  getting  into  the  cultivated  field,  as  are  mentioned  above. 


TEXAS    FKVKK    AND    ITS    I'KKVKNTION.  39 


JMMl  AI/ATION    OK    SI  SCKITIItl.K    CATTI.K. 


By  blood  inoculation. — It  is  often  desirable  to  ship  well-bred  cat- 
tle into  infested  districts,  that  they  may  he  used  to  improve  the 
quality  of  the  native  cattle  already  there.  Previous  to  the  discov- 
ery of  the  cause  of  Texas  fever,  it  was  found  to  he  wellnigh  impos- 
sible to  introduce  purebred  cattle  from  the  North  into  any  of  the 
infected  regions  without  suffering  great  loss — sometimes  as  high 
as  90  per  cent — within  a  few  months  of  their  arrival  at  their  South- 
ern destination.  At  first  it  was  thought  that  the  fatalities  were  due 
to  climatic  changes,  but  later  the  discovery  was  made  that  Texas 
fever  was  causing  these  numerous  deaths. 

It  has  now  been  found  practicable  to  immunize  this  class  of  cattle 
so  perfectly  that  the  losses  which  follow  their  transportation  to  a 
tick-infested  region  are  reduced  to  a  minimum.  Young  animals  six 
to  fifteen  months  old  should,  so  far  as  possible,  be  selected  for  this 
purpose,  as  they  are  more  readily  immunized  than  adults,  are  more 
.easily  handled,  and  the  dangers  which  may  arise  from  pregnancy 
while  undergoing  the  immunizing  treatment  are  thus  avoided. 

Immunity  in  these  cattle  is  obtained  by  introducing  the  micro- 
parasite  of  the  blood  into  their  systems.  It  may  Ix*  done  by  direct 
artificial  inoculation  or  by  placing  virulent  young  ticks  upon  the 
animals  and  allowing  them  to  perform  the  inoculation  in  the  natural 
manner.  The  subcutaneous  injection  of  a  small  amount  of  defibri- 
nated  virulent  blood  has  been  found,  by  means  of  prolonged  ex|M>ri- 
iiient,  the  preferable  method,  as  the  number  of  microorganisms  intro- 
duced can  be  more  accurately  gauged  from  the  syringe  than  by 
allowing  the  infection  to  be  produced  by  bites  of  ticks.  Two  or 
three  inoculations,  if  repeated  at  proper  intervals,  are  accomplished 
with  greater  safety  to  the  animal  than  would  be  possible  by  means 
of  a  single  inoculation.  The  amount  first  injected  should  l>e  small 
and  then  gradually  increased  in  the  succeeding  treatments. 

The  inoculation  always  results  in  a  more  or  less  serious  attack  of 
Texas  fever.  Besides  having  a  fever,  there  is  great  diminution  of 
red  blood  corpuscles,  and  in  about  tt  per  cent  of  the  eases  a  fatal  termi- 
nation; but  the  proportion  of  deaths  resulting  from  the  inoculation  is 
small  when  compared  with  the  fatalities  among  untreated  animals 
taken  into  infested  districts.  To  this  number  should  IH>  added  those 
animals  (less  than  7  per  cent)  that  do  not  receive  sufficient  immunity 
by  this  method  and  which  succumb  when  exposed  to  infested  pastures. 
Combining  these  failures  it  will  be  seen  that  by  this  method  of  im- 
munization, instead  of  a  loss  of  5)0  per  cent  among  breeding  stock 
taken  South  more  than  00  per  cent  can  be  saved.  The  animals  should 
be  carefully  nursed  through  the  attack  and  their  symptoms  treated 
as  indicated  on  page  20, 


40  BUREAU  OF  ANIMAL  INDUSTRY. 

Immunizing  inoculations  are  now  being  made  by  the  veterinarians 
r>f  most  of  the  agricultural  experiment  stations  of  the  Southern  States 
without  cost  for  the  services  rendered,  a  charge  lx»ing  made  merely 
for  the  actual  value  of  food  consumed  and  attendants'  wages.  These 
veterinarians  have  also  issued  station  bulletins  which  deserilx'  fully 
the  necessary  steps  to  be  taken  in  securing  the  blood  and  injecting  it 
into  the  animals  to  be  immunized,  so  that  the  stock  owner  can  follow 
the  instructions  with  prospects  of  getting  good  results. 

This  operation  is  not  a  difficult  one,  and  excellent  results  will  follow 
where  absolute  cleanliness  and  ordinary  care  have  l)een  used,  but 
undoubtedly  the  lx»st  results  will  lx>  obtained  by  those  who  have 
thoroughly  familiarized  themselves  with  the  nature  of  the  disease 
and  are  experienced  in  extracting  blood  from  animals.  Two  methods 
are  in  use  and  will  be  described  separately.  One  consists  in  drawing 
the  blood  from  the  jugular  vein  of  an  immune  animal  and  immedi- 
ately injecting  it  into"the  cattle  to  lx>  immunized.  It  is  compara- 
tively simple,  requires  few  instruments,  and  can  be  satisfactorily 
carried  out  where  a  small  number  of  animals  are  to  be  immunized 
and  if  a  suitable  immune  animal  is  close,  at  hand.  First,  select  an 
immune  animal  which  is  in  good  health  and  which  is  infested  with 
fever  ticks  or  had  them  the  preceding  year.  Fasten  the  animal 
securely,  either  by  tying,  throwing,  or  by  placing  in  a  chute.  Clip 
the  hair  from  a  space  about  4  inches  in  diameter  over  the  jugular  vein 
on  the  upper  third  of  the  neck,  wash  the  skin  thoroughly  with  a  5  per 
cent  solution  of  carbolic  acid,  and  then  fasten  a  strap  or  rope  around 
the  neck  below  the  hairless  area  and  draw  it  tight  in  order  that  the 
blood  in  the  vein  will  lx»  stopped,  causing  distention.  With  a  large 
hypodermic  syringe  needle  previously  sterilized  in  a  5  per  cent  car- 
bolic-acid solution,  puncture  the  vein  at  a  slight  angle,  directing  the 
point  forward.  When  the  needle  enters  the  vein  the  point  can  In- 
rotated  freely  in  contrast  to  the  restricted  movements  if  still  in  the 
tissues,  and  the  blood  will  either  drop  or  flow  from  the  opening  in  the 
needle.  Attach  the  disinfected  syringe  to  the  needle  with  piston  in 
and  gradually  draw  out  the  piston  until  the  chamber  of  the  syringe 
is  full  of  blood  when  the  needle  is  withdrawn.  The  blood,  before  it 
has  had  time  to  clot,  is  immediately  injected  into  the  animals  to  IK? 
immunized  and  which  have  lx»en  previously  tied  or  restrained,  the 
hair  clipped,  and  the  skin  disinfected  at  the  seat  of  injection  in  the 
region  of  the  shoulder.  Inject  then  from  1  to  tt  cubic  centimeters, 
according  to  the  age  of  the  animal,  under  the  skin  of  each  animal 
until  the  blood  is  exhausted.  When  more  animals  are  to  be  inoculated 
than  one  syringeful  will  inject,  the  operation  may  lx>  repeated  in  the 
same  manner.  The  only  objection  to  this  method  is  the  possibility  of 
the  blood  clotting  in  the  syringe,  but  with  practice  and  promptness 
this  can  be  easily  overcome. 


TEXAS    FEVER    AND    ITS    PREVENTION.  41 

The  second  method  is  better  suited  for  the  inoculation  of  a  large 
number  of  cattle  or  where  the  immune  animal  is  at  a  distance  from 
the  cattle  to  be  immunized. 

The  preliminary  steps — the  clipping  of  the  hair,  disinfection  of 
the  skin,  placing  the  rope  around  the  neck  to  distend  the  jugular 
vein,  and  restraining  the  animal — are  the  same  as  for  the  first  method. 
In  puncturing  the  vein  it  is  advisable  to  use  a  small  trocar  and  canula 
after  sterilization  in  a  5  per  cent  carbolic-acid  solution,  and,  when 
the  vein  has  been  entered,  to  draw  out  the  trocar,  allowing  the  blood 
to  flow  through  the  canula  into  a  perfectly  clean  and  sterile  vessel. 
After  sufficient  blood  has  been  drawn  for  the  animals  to  be  injected, 
a  clean  stick,  previously  sterilized  by  boiling  in  water,  is  placed  in 
the  vessel  containing  the  blood  and  the  latter  is  stirred  for  ten  min- 
utes or  so  or  until  the  fibrin  in  the  blood  is  whipped  out.  The  remain- 
ing blood,  known  as  defibrinated  blood,  is  then  inoculated  under  the 
disinfected  skin  of  the  animals  to  be  immunized,  as  in  the  first 
method.  This  blood  should  l>e  used  as  early  as  possible  after  draw- 
ing, to  prevent  it  from  becoming  contaminated  and  decom posed. 
The  place  where  this  injection  is  made  is  immaterial,  but  for  conven- 
ience a  point  just  behind  the  shoulder  is  usually  chosen.  The  dose 
and  number  of  injections  vary  with  the  individual  animals.  As  a 
ride,  it  may  be  stated  that  1  cubic  centimeter  should  be  injected  into 
an  old  animal  coming  into  the  infested  district,  2  cubic  centimeters 
for  a  '2-year-old,  and  H  centimeters  for  an  animal  i>  to  1.")  months  old. 
It  will  be  observed  that,  unlike  the  usual  custom  of  applying  treat- 
ment, the  older  animals  take  less  than  the  young  ones,  owing  to  their 
greater  susceptibility  to  the  disease.  Where  an  animal  has  reacted 
well  to  a  first  injection  and  shows  a  very  high  temperature,  great 
reduction  of  red  blood  cells,  or  other  symptoms  indicative  of  reac- 
tion, it  will  not  be  necessary  to  repeat  the  injection,  but  in  those 
cases  where  the  reaction  is  slight,  a  second  injection  should  follow 
after  an  interval  of  forty  days,  and.  if  need  be,  a  third  injection  after 
a  similar  lapse  of  time,  always  increasing  the  size  of  dose  .">()  per  cent. 
A  thermometer,  to  indicate  the  course  and  severity  of  the  disease, 
is  indispensable  in  this  work.  Usually,  after  three  to  ten  days,  some- 
times longer,  the  inoculated  animals  show  a  mild  type  of  Texas  fever, 
which  runs  a  course  of  from  six  to  eight  days  and  is  followed  in  alxmt 
thirty  days  after  the  injection  with  a  second  attack  of  a  milder 
character  than  the  first.  After  forty  days,  when  the  animal  has 
entirely  recovered  from  the  inoculation,  a  second  injection  may  be 
given  to  increase  its  immunity.  In  some  eases  a  very  severe  type  of 
fever  follows  the  first  inoculation,  requiring  careful  nursing  and 
treatment,  as  suggested  above.  A  second,  milder  attack  follows 
usually  in  about  thirty  to  forty  days,  after  which  the  animal  need 
have  no  further  inoculations.  It  is  advisable  to  prevent  any  ticks 


42  Bt'RKAU   OF    ANIMAL   INDUSTRY. 

from  getting  °n  the  cattle  until  sixty  days  after  their  inoculation  or 
until  they  have  fully  recovered,  at  which  time  a  few  ticks  may  be 
placed  upon  them  in  order  to  it-enforce  their  immunity.  Naturally 
this  time  varies  according  to  the  type  of  the  attack.  As  the  lx»st 
results  with  these  immunizing  experiments  have  t>een  obtained  in 
cool  weather  and  with  young  cattle,  it  is  recommended  that  animals 
from  6  to  15  months  old  l>e  selected  for  inoculation,  and  that  they 
be  immunized  during  the  late  fall  or  winter  months,  in  order  that 
they  may  enter  tick-infested  pastures  in  the  spring  without  danger. 
Ry  infextiny  irith  tick*. — Immunity  may  also  be  induced  in  sus- 
ceptible animals  by  placing  a  limited  number  of  fever  ticks  upon 
their  bodies  in  order  to  produce  the  disease  naturally.  For  this  pur- 
pose only  animals  less  than  1  year  of  age  should  l>e  used,  as  the 
method  is  not  applicable  for  older  and  more  susceptible  animals. 
Upon  the  bodies  of  these  young  cattle  from  twenty-five  to  fifty  seed 
ticks  should  be  placed,  which  in  the  course  of  about  ten  days  will 
occasion  a  rise  of  temperature  and  a  mild  form  of  Texas  fever.  When 
the  animal  has  entirely  recovered  from  this  attack,  a  second  crop — 
double  the  inunlx>r  first  used — should  be  applied  to  the  animal  in 
order  to  increase  its  power  of  resistance  when  pastured  on  infested 
soil.  In  order  to  carry  out  this  method  successfully,  a  constant  sup- 
ply of  seed  ticks  must  be  at  hand.  This  can  lx'  accomplished  by  plac- 
ing the  mature  females  in  a  Mason  fruit  jar  among  some  dirt  and 
leaves  and  keeping  them  in  a  warm  place.  In  a  few  weeks  the  eggs 
will  have  lx>en  laid  and  hatched,  and  a  number  of  seed  ticks  will  be 
present  for  use  in  infesting  the  cattle  to  Ix;  immunized.  By  placing 
a  few  adult  females  in  the  jar  every  two  months  there  will  always  be 
a  supply  of  these  young  ticks.  This  method  of  producing  immunity 
by  controlled  tick  infestation  is  not  so  safe  as  blood  inoculation,  since 
the  quantity  of  germs  injected  can  Ix;  more  accurately  regulated  by 
means  of  a  syringe. 

FEDERAL  SANITARY  REGULATIONS. 

The  sanitary  regulations  which  have  lx»en  enacted  by  the  Depart- 
ment of  Agriculture  for  the  control  of  cattle  shipments  from  the  in- 
fected districts  have  for  their  initial  purpose1  the  prevention  of  the 
transportation  of  cattle  ticks  from  infected  regions  to  those  that 
are  not  infected,  either  upon  cattle  or  in  stock  cars  or  other  conveyer, 
during  the  season  of  the  year  when  infection  is  possible.  They  are 
based  upon  the  fact  that  Texas  fever  is  carried  north  only  by  the 
cattle  tick;  and  the  exclusion  of  this  parasite  from  the  noninfected 
territory  has  in  every  instance  lx»en  found  a  certain  method  of  ex- 
cluding Texas  fever.  The  regulations  governing  the  movement  of 
cattle  from  Ix'low  the  quarantine  line  are  made  yearly  by  the  Secre- 
tary of  Agriculture  and  they  define  the  Ixmndary  of  infected  dis- 


TEXAS  FEVER  AND  TTS  PREVENTION.  48 

tricts.  The  line  as  now  determined  starts  in  Virginia  on  the  Atlantic 
coast  and  passes  in  a  westerly  direction  through  Virginia,  North 
Carolina,  Georgia,  Tennessee,  and  a  small  portion  of  Kentucky, 
along  the  northern  border  of  Arkansas  and  Indian  Territory,  thence 
through  Oklahoma  and  Texas  to  the  Kio  Grande  and  the  Mexican 
border,  whence  it  passes  along  the  southern  boundary  of  New  Mexico 
and  Arizona  and  across  the  central  portion  of  California  to  the 
Pacific  slope  (fig.  1).  This  year  (1905)  cattle  may  IK*  moved  from 
the  quarantined  district  for  purposes  other  than  immediate  slaughter 
during  November,  December,  and  January  into  the  noninfected 
area  within  the  States  of  Virginia,  North  Carolina,  Georgia,  Ten- 
nessee, Texas,  Oklahoma,  and  California,  and  to  the  States  of  Mis- 
souri and  Kansas  and  the  Territories  of  Arizona  and  New  Mexico,  as 
may  be  provided  for  in  the  regulations  of  these  States  and  Terri- 
tories, and  after  inspection  by  and  upon  written  permission  of  an 
inspector  of  the  Bureau  of  Animal  Industry  or  a  duly  authorized 
inspector  of  the  State  or  Territory  to  which  the  cattle  are  destined, 
and  after  permission  shall  have  been  obtained  from  the  proper  officer 
of  the  said  State  or  Territory.  All  cattle  from  the  quarantined  district 
destined  to  points  outside  of  the  States  and  Territories  above  named 
may  be  shipped  without  inspection  between  November  1  and  January 
31,  inclusive  (the  open  season),  without  restrictions  other  than  may 
be  enforced  by  local  regulations  at  the  point  of  destination.  At  the 
present  time  no  cattle  shall  go  out  of  quarantine,  except  for  immediate 
slaughter,  during  that  portion  of  the  year  included  between  the  dates 
of  February  1  and  October  31,  and  known  as  the  closed  season. 
These  cattle  must  be  slaughtered  within  two  weeks  after  arrival  at 
their  destination,  and  the  regulations  of  the  Secretary  of  Agriculture 
concerning  their  handling  and  movement  shall  be  enforced.  The 
following  is  an  abstract  of  the  regulations  in  force  May  1,  1005: 

Cattle  coming  from  the  infected  districts  during  the  closed  season 
can  not  be  driven,  but  must  be  conveyed  in  cars  or  boats  placarded  as 
containing  "  Southern  cattle,"  and  bills  of  lading,  waybills,  and  con- 
ductors1 manifests  shall  have  this  information  written  upon  them. 
When  the  cattle  are  unloaded  for  feeding,  watering,  or  other  pur- 
pose they  must  be  placed  in  pens  reserved  for  such  animals  only,  in 
which  native  stock  is  not  allowed,  and  a  large  sign  with  the  words 
"  Quarantine  pens  "  or  "  Quarantine  yards  "  must  be  conspicuously 
placed  on  all  such  inclosures.  On  unloading  at  their  destination, 
only  the  chutes,  alleyways,  and  pens  reserved  for  Southern  cattle 
shall  be  used.  Before  the  cars  or  boats  which  carried  these  animals 
are  again  used  their  entire  interior  must  be  thoroughly  washed  with 
water,  after  the  removal  of  all  litter  and  manure,  and  then  disinfected 
with  a  mixture  made  of  1.1  pounds  of  lime  and  }  pound  of  100  {x*r 
cent  carbolic  acid  to  each  gallon  of  water,  or  with  a  solution  made 


44  BUREAU  OF  ANIMAL  INDUSTRY. 

by  dissolving  4  ounces  of  chloride  of  lime  to  each  gallon  of  water. 
The  litter  and  manure  may  U'  disinfected  as  above,  or,  if  not  disin- 
fected, it  shall  lx>  stored  away  where  cattle  can  not  reach  it  during 
the  period  from  February  1  to  October  HI  of  each  year.  All  chutes, 
alleyways,  and  pens  used  en  route  and  at  destination  but  not  reserved 
for  the  exclusive  use  of  Southern  cattle  shall  lx>  similarly  disinfected. 
Where  these  animals  are  yarded  adjacent  to  cattle  from  above  the 
line,  at  least  a  10-foot  space  not  occupied  by  cattle  must  be  left  be- 
tween, on  each  side  of  which  shall  be  a  tight  board  fence  not  less 
than  5  feet  high. 

In  consequence  of  the  enforcement  of  these1  quarantine  regulations 
Texas  fever  has  lx>en  practically  prevented  in  the  non infected  dis- 
tricts during  the  last  several  years,  and  little  or  no  hardship  has  been 
caused  to  those  stockmen  handling  cattle  from  the  infected  areas. 
Previous  to  their  adoption  the  tick-infested  district  was  rapidly  ex- 
tending northward,  but  since  the  quarantine  line  was  established  and 
rational  regulations  enforced  it  has  gradually  been  moved  farther 
south.  This  problem  of  still  further  reducing  the  infected  area  is  of 
the  greatest  importance  to  the  cattlemen  of  the  South — in  fact,  to 
those  on  both  sides  of  the  line — and  one  which  is  receiving  special 
consideration  by  this  Department  as  well  as  by  many  of  the  inter- 
ested States. 

OTIIKR    IMPORTANT    MEASURES    FOR   REDICINC   THE    INFECTED   AREA. 

The  first  and  probably  the  most  important  step  in  eradicating  the 
cattle  tick  is  to  start  and  continue  a  plan  of  educating  the  cattle  owner 
as  to  the  nature  of  Texas  fever  and  the  method  of  its  transmission. 
This  may  be  best  accomplished  through  farmers'  institutes,  the 
issuance  of  press  bulletins  and  circluars.  the  publication  of  short 
articles  in  agricultural  journals,  and,  l>est  of  all.  by  personal  inter- 
course Ix'tween  the  agricultural  population  and  educated  stock  in- 
spectors who  are  capable  of  imparting  the  necessary  information. 
There  can  be  no  doubt  that  the  crying  need  of  the  infected  country  is 
not  so  much  the  development  of  new  ideas  for  exterminating  the 
cattle  tick  as  it  is  to  remove  all  doubts  of  stockmen  regarding  what 
they  term  the  "tick  theory,"  and  to  impress  upon  them  the  funda- 
mental truths  concerning  the  cattle  tick,  its  relation  to  Texas  fever, 
and  simple  methods  for  its  extermination.  In  other  words,  the  stock- 
man himself  must  lx>  made  to  realize  the  proved  facts  regarding  this 
disease,  and  then  to  appreciate  the  feasibility  of  eradicating  the  ticks 
which  cans*1  it.  There  is  still  a  large  number  of  cattlemen  who  are 
incredulous  regarding  the  nature  of  Texas  fever  and  until  the  abso- 
lutely established  facts  of  the  disease  are  known  and  accepted  it  will 
be  impossible  to  have  intelligent  cooperation  and  earnest  endeavor 


TEXAS  FEVER  AND  ITS  PREVENTION.  45 

among  those  most  vitally  interested  to  eradicate  the  Texas- fever  tick 
and  prevent  the  disease.  In  some  counties  within  the  infected  dis- 
trict bordering  on  the  quarantine  line  the  local  authorities  have 
organized  cattle  clubs  composed  of  stockmen  with  the  view  of  inter- 
esting them  in  exterminating  the  ticks  from  their  premises,  and  in 
preventing  cattle  in  adjoining  tick-infested  sections  from  coming 
upon  their  property.  These  organizations  are  the  means  of  dissemi- 
nating general  information  respecting  Texas-fever  infection  and  the 
cause  of  the  restrictions  placed  on  the  cattle  in  the  infected  district, 
and  through  them  a  concerted  action  of  the  cattle  owners  is  obtained, 
resulting  in  the  control  and  final  eradication  of  the  infection  within 
a  portion  or  the  whole  of  a  county.  When  a  county  has  been  handled 
in  this  manner  a  thorough  inspection  is  made  at  the  proper  time  by  a 
representative  of  the  Bureau  of  Animal  Industry,  and  if  the  condi- 
tions warrant  such  action  it  is  released  from  quarantine.  The  success 
of  such  clubs  in  accomplishing  both  these  purposes  is  a  constant  re- 
minder of  what  other  organized  stockmen  could  do.  The  desirability 
of  rational  legislation  based  on  an  accurate  knowledge  and  a  complete 
understanding  of  the  disease  is  self-evident.  Every  county  in  all  the 
infected  States  should  have  stock  or  "  no  fence  "  laws  to  prevent 
stock  owners  from  allowing  ticky  cattle  on  commons,  uninclosed 
lands,  or  highways.  Especially  should  these  be  enforced  in  the  States 
on  the  quarantine  line  and  in  those  having  many  noninfected  areas  in 
the  quarantined  region.  In  the  former  case  this  would  assist  in 
securing  a  position  above  the  line,  and  in  the  latter  it  would  tend  to 
enlarge  the  tick-free  sections.  In  a  number  of  counties  in  Virginia, 
North  Carolina,  and  Georgia,  where  the  laws  prohibit  cattle  from 
running  at  large  and  compel  fencing  of  pastures,  the  cattle  tick  soon 
disappeared,  and  such  tick-free  counties  were  placed  above  the  quar- 
antine line  without  any  loss  having  followed  from  the  cattle  in  these 
districts.  Butler  suggests  that  each  county  should  have  laws  pro- 
viding for  a  farm-to-farm  inspection,  with  employment  of  a  stock 
inspector,  in  order  to  locate  the  tick-infested  farms.  Stockmen 
themselves  should  organize  in  order  to  aid  the  county  in  its  endeavor 
to  exterminate  the  ticks;  and  information  concerning  their  habits, 
the  importance  of  their  extermination,  and  methods  for  accomplish- 
ing it  should  be  furnished  to  owners  of  infected  lands.  With  the 
active  cooperation  of  the  people  and  the  enforcement  of  the  stock 
laws,  much  territory  may  be  freed  of  ticks  at  a  very  moderate  annual 
expense.  If  ticks  on  one  farm,  one  section,  one  county,  can  lx>  ex- 
terminated, it  certainly  should  be  possible  for  the  entire  State  or 
entire  infested  district  to  be  cleaned. 

In  all  the  infected  States  a  uniform  legislation  should  lx>  secured  on 
the  subject  of  communicable  diseases,  particularly  Texas  fever,  by 


4tt  BUREAU    OF    ANIMAL    INDUSTRY. 

which  these  States  would  l>e  enabled  not  only  to  cooperate  with  the 
Federal  Government,  but  also  with  each  other.  Such  laws  should 
prevent  the  entrance  of  ticky  cattle  into  the  State,  unless  for  slaughter, 
compel  the  holding  of  cattle  on  inclosed  premises,  enforce  an  effectual 
quarantine  on  all  badly  infected  areas,  make  it  compulsory  to  clean 
up  the  infection  where  the  ticks  are  few  in  numl>er,  and  stipulate 
that  the  stock  inspectors  appointed  for  this  work  must  be  educated 
and  experienced  in  the  subject  of  Texas  fever.  Then,  after  securing 
these  laws  in  the  various  States,  they  should  IH>  enforced,  all  violat- 
ers  should  IK«  punished,  and  such  punishments  should  be  given  wide- 
spread publicity.  Such  action  is  absolutely  necessary  before  any 
decided  progress  can  lx»  made  in  the  general  extermination  of  the 
fever  ticks  and  in  the  reduction  of  the  infected  areas. 

For  some  years  past  the  Bureau  of  Animal  Industry  has  had  a 
numlx'r  of  inspectors  stationed  along  the  quarantine  line  who  have 
been  required  to  disseminate  information  relative  to  the  nature  of 
Texas  fever,  to  investigate  reported  violations  of  the  quarantine 
regulations,  to  inspect  cattle  in  those  counties  wishing  to  be  placed 
alx>ve  the  line,  to  keep  a  careful  watch  over  the  uninfected  pens  at  the 
railroad  feeding  stations  in  the  infected  district  where  tick-free  cattle 
are  rested,  fed,  and  watered  in  passing  through,  and  to  examine  for 
the  presence  of  ticks  all  cattle  that  come  out  of  the  modified  quaran- 
tined counties.  These  modified  districts  are  those  wherein  the  infec- 
tion is  confined  to  small  areas  and  which  are  placed  provisionally 
alM)ve  the  line  subject  to  inspection  of  all  cattle  leaving  that  area  for 
noninfected  territory.  Xo  cattle  are  permitted  to  come  into  the  dis- 
trict unless  they  come  from  above  the  quarantine  line.  In  certain 
cases  where  a  county  has  only  a  few  infected  farms,  the  Department 
has  at  times  accepted  the  declaration  made  by  the  State  officials  to 
enforce  an  adequate  quarantine  on  these  premises  and  has  allowed  tin1 
entire  county  to  be  placed  above  the  line.  Such  concessions  as  these 
indicate  the  interest  taken  in  relieving  the  burden  of  quarantine,  and 
while  some  unfortunate  results  have  followed,  the  Ix'neficial  effects 
have  far  exceeded  them. 

The  authority  of  the  Federal  veterinary  inspectors  is  limited  within 
the  iMHindary  of  the  States,  and  the  progress  they  are  able  to  make 
under  these  conditions  is  slow.  In  order  to  give  these  men  greater 
influence  within  the  State,  it  might  be  advisable  to  have  the  State  law 
permit  of  their  appointment  as  officers  of  the  commonwealth  to  serve 
without  compensation.  Thus,  in  the  eradication  of  foot-and-mouth 
disease  from  New  Kngland  and  of  scabies  from  the  West,  some  States, 
such  as  Massachusetts,  Wyoming,  and  others,  made  State  officers  of 
the  Government  men,  which  resulted  in  a  larger  amount  of  work 
l>eing  performed  and  with  greater  expedition.  The  restrictions 
which  are  necessarily  thrown  around  a  Federal  inspector  when  deal- 


TEXAS    FEVER   AND    ITS    PREVENTION.  47 

ing  with  a  local  question  of  interstate  importance  would  by  these 
means  be  relieved. 

It  would  be  advisable  for  the  State  or  Federal  Government,  or 
both,  to  make  sufficient  yearly  appropriations  for  the  purpose  of  giv- 
ing object  lessons  by  means  of  demonstration  farms,  where  approved 
methods  for  eradicating  Texas-fever  ticks  could  be  carried  out.  Re- 
sults of  such  practicable  demonstrations  would  have  a  very  whole- 
some effect  upon  other  owners  of  stock  in  that  section  and  would 
encourage  the  application  of  similar  methods  for  a  like  purpose. 
It  is  generally  admitted  that  extermination  of  ticks  along  the  quar- 
antine line  is  desirable,  but  the  disinfection  of  pastures  within  the 
line  is  thought  by  some  to  be  inadvisable.  In  fact,  these;  writers 
recommend  placing  a  few  ticks  on  the  cattle  while  young  to  render 
them  immune  when  in  these  tick-free  pastures.  This  plan  of  infect- 
ing clean  pastures  is  a  questionable  proceeding,  and  if  carried  out 
by  all  below  the  line  would  result  in  producing  thousands  of  ticks 
where  now  there  are  hundreds  only.  It  must  be  remembered  in  this 
connection  that  the  cow  tick  is  not  only  the  carrier  of  Texas  fever,  but 
is  a  parasite  which  deprives  its  host  of  much  blood,  retards  growth, 
reduces  the  milking  capacity,  and  induces  an  irritable  state  known 
as  "  tick  worry."  Even  if  we  exclude  its  fever-carrying  property, 
it  should  still  be  exterminated  in  all  districts,  whether  on  the  quar- 
antine line  or  below  it,  for  the  same  reasons  as  lice  and  other  vermin 
are  destroyed.  Furthermore,  cattle  may  now  be  rendered  immune 
by  blood  inoculations,  and  the  necessity  for  having  ticks  on  the  ani- 
mals for  this  purpose  does  not  exist.  It  would  therefore  seem  pref- 
erable to  keep  noninfected  farms  free  from  ticks,  and,  if  they  are 
in  danger  of  exposure  to  these  parasites,  make  the  animals  immune 
by  blood  injections.  If  these  injections  are  made  merely  with  the 
Adew  of  preventing  fatalities  among  the  nn infested  cattle  when 
exposed  to  newly  purchased  ticky  animals,  it  would  l>e  far  Ix'tter  to 
remove  the  ticks  from  the  latter  before  allowing  them  to  commuigle. 
Others  buying  these  susceptible  cattle  for  their  own  infected  pas- 
tures would  also  run  the  risk  of  their  death  from  Texas  fever  unless 
previously  immunized  with  blood  or  gradually  infested  with  ticks. 
Notwithstanding  the  precautions  which  must  be  taken  to  avoid 
losses  as  a  result  of  noninfected  areas  in  the  quarantined  zone,  it  is 
held  that,  unless  these  pastures  continue  free  of  ticks  and  other  pas- 
tures are  added  to  them,  there  can  be  no  solution  of  the  Texas-fever 
problem. 

It  might  be  asked.  What  advantage  is  it  to  the  stockman  below  the 
line  to  clean  his  cattle  and  pastures  of  ticks  unless  his  animals  are 
recognized  as  tick-free  and  permitted  to  come  North  without  restric- 
tion? The  greatly  improved  condition  and  better  development  in 
all  respects  of  such  cattle  are  sufficient  answers  to  this  query,  and  their 


48  BUREAU  OF  ANIMAL  INDUSTRY. 

appearance  furnishes  a  marked  contrast  to  that  of  those  which  harlx>r 
these  parasites.  Furthermore,  provision  has  been  made  for  mm  in 
feeted  animals  to  come  al>ove  the  line  at  any  season  of  the  year,  but. 
like  the  ticky  cattle,  they  are  subject  to  the  restriction  that  they  be 
dipped  in  Heaumont  crude  jx'troleum  or  other  crude  oil  to  prevent 
them  from  Incoming  infested  in  passing  through  the  quarantined  dis- 
trict. And  they  must  also  l>e  shipped  in  clean,  disinfected  cars,  and 
must  not  l>e  driven  through  the  infected  area  or  unloaded  therein  ex- 
cept at  points  designated  by  this  Department. 

By  the  general  application  of  the  previously  descrilx'd  measures  for 
reducing  the  infected  area,  supported  by  well-directed  legislation  in 
all  the  infected  districts,  it  would  become  merely  a  matter  of  a  short 
period  of  time  Ix-fore  the  fever  tick  would  l>e  exterminated  and  South- 
ern cattle  permitted  to  reach  the  more  favorable  markets  of  the  North 
at  any  time  of  the  year  without  restraint.  Prices  would  then  be 
higher,  the  demand  greater,  and  the  odium  attached  to  ticky  cattle  at 
the  stock  yards  removed.  Purebred  Northern  cattle  could  then  l>e 
brought  into  the  South  to  improve  the  native  breed  without  danger  of 
death  from  Texas  fever.  Southern  animals  could  enter  the  show  rings 
of  the  North  without  restriction,  and  the  total  cost  of  tick  extermina- 
tion would  be  far  less  than  the  amount  saved  in  the  first  year  after  it 
had  been  accomplished.  However,  much  cooperation  must  be  had 
J»etween  the  farmer  and  the  State  and  Federal  Governments  before 
such  a  desirable  result  is  possible.  And  in  the  meantime,  with  such 
conditions  attainable,  laxity  should  not  be  allowed  in  enforcing  the 
present  regulations.  National.  State,  and  local,  and  equal  care  should 
!K>  taken  to  enlighten  the  stock  raisers  of  the  infected  district  as  to 
the  l>eneh'ts  which  will  follow  their  thorough  understanding  of  Texas 
fever  and  their  intelligent  assistance  in  its  eradication. 


o 


•led  from  paKe  ?  of  cover.) 


Dr.  F.  I).  Ketchuii.  •-Mill.  Minn. 

Dr.  W.  15.  Lincoln,  can'  Tt-nni-sM'.-  Packini,'  and 

Provision  Co.,  Xa-livillc.  Tcim. 
Dr.  A.  LOOK,  ean-  ^pcn  '••'•«•   Hiivi.-n, 

Conn. 

Dr.  C.  Lovcbern  ,  room   in.',  CUBtOIH;bonae  (new), 

Portland,  On-u. 

Dr.  II.  D.  Maync,  Malone.  X.  V. 
Dr.  Louis  Meeker,  room  21'.  N.  T.  Armijo   Build- 
ing. All>U'|uerc|ue.  N.  Mex. 
Dr.  .1.  Miller,  care  John  Morrell  A:  Co.,  Ottumwa, 

Iowa. 

Dr.  C.  L.  M.irin,  St.  Albans  Vt. 
Dr.   A.    H.    Morse,    can-    The  Atrar    I'a<-king  Co., 

Dr>-  Moines.  Iowa. 
Dr.  \V.  .1.  Murphy,  care  SpriiiKlicld  Provision  Co.. 

Bright  wood.  Ma—-. 
Dr.  W.  X.  Xcil.  care  John   Cudnhy  Co..  Wichita. 

Kans. 
Dr.  V.  A.  NSrgaanJ,  Honolulu,  Hawaii. 

M.  I'.Try.  Fort  Kairticld.  Me. 
Dr.  (i.  \V.    l'o|"%    Animal   Quarantine   station, 

Athenia,  X.  .1. 
Dr.  H.  T.  Potter.  Culiiis,  Me. 
Dr.  .1.  O.  F.  Price,  care  Brittain  &  Co..  Marshall- 

to\vn.  Iowa. 

Dr.  R.  A.  Ramsay.  Far^o,  X.  Dak. 
Dr.  A.  Q,  «i.  EUchaidaon,  707  Empire  Building, 

Knoxville,  Tenn. 


Dr.  A.  K.  l;i«.|ii-l.  can-  Cndahy   I'nckiiiR-  Co.,  Los 

Dr.  \\ .  II.  K. 

Dr.  K.  L.  KH--.-H.  orono.  Me. 
Dr  .1.  F.  Ky.I.T.  1  11  Mil.  -n.  Mass. 

Dr.  K.  P.  SchafTter 
•  •ill'!.  Ohio. 
Dr.  C.  A.SelmufliT.  I'hila- 

delphin.  Pa. 
Dr.  ThoM.  \\     - 

Waterloo.  Iowa. 
Dr.  T.  A.  Shipley,  care  T.  M.  Sinclair 

r  Rapids,  Iowa. 
Dr.  X.  C.  Sorcii-cn.  care  Kintrnn  &  >;,..  Indian- 

ajiolis,  Ind. 
Mr.  Win.  H.  Wade,  Animal    Qiianur 

Halcthorp.  Md. 
Dr.  A.  H.  \\,  Aorth. 

Dr.   II.  X.  Waller.    10'J  \\ 

Xew  York.  X.  Y. 
Dr.  <i.  W.  Ward.  N.-\vjK,rt.  Vt. 
Dr.  B.  P.  Wende.  Live  stock  Fxclmi 

ifTalo.  X.  Y. 
Dr.  W.  H.  Wray,  :14  Streathum  Hill 

W.,  England. 


A    001  083  175     8 


